This makes sense!
I can relate to this also because I remember before I was really lured to altcoins. Even I started with Bitcoin, like some of my Bitcoins before were converted to altcoins and I lost so much, after that I learned the lesson and started to hold and focus more on Bitcoin instead of altcoins.

Bitcoin is the king of crypto and of course no one can beat it. However, yes, there are quite a few people who invest in Altcoins that are of poor quality with the aim of getting rich quickly, but those who are lucky will indeed get extraordinary profits and of course they will not give up on investing in Altcoins or others. However, those who experience losses will certainly give up on investing in Altcoins and will definitely end up investing in Bitcoin because they learn from experience and think that Bitcoin is the safest crypto.

To be honest, I was also in a situation where I experienced losses due to investing in Altcoins that were not of good quality and up to now I believe Bitcoin is still the safest but I also invested in Altcoins but only a little but still the money I use most is to buy Bitcoin most of the because I personally have tasted the sweetness of investing in bitcoin.

Yes, experience is a valuable teacher and indeed beginners sometimes experience losses when they invest because they are not investing in Bitcoin. However, experiencing bitter experiences has made some people realize that BTC is the best.

I think it would depend on every traders, there are traders who would spread out their investment, and wouldn't focus on single trade to lessen the risk.
But I do get the point all the other project mostly airdrop would only be used to make our portfolio grow bigger.

Oh yes, there is!
How many shops do you have around you that accept crypto?
How many people invest in stocks and have a bank account and how many actually have a crypto address?
Once you log out of this forum how many around you are actually interested in crypto?

Taken over the world? Be serious!
There are barely 40 million addresses with more than 1$ balance on the whole chain while we have 2 billion debit cards and you talk about "taking over the world"?

Some people need a reality check, once you close twitter and other social media where you follow only crypto you will realize how large this world is and crypto has barely made a dent in it, it's a long long long way to go!!!

I disagree.

Airdrop isn't a coin or token.

What you want to say is: big cap altcoins > low cap altcoins > newly listed coins > Bitcoin.

Some people might turn become Bitcoin investors, but if they hold their Bitcoin in centralized exchange and the CEX bankrupt, I doubt they will want to buy and hold Bitcoin again.

Most likely the scenario is: Bitcoin > Big cap altcoins > low cap altcoins > newly listed coins > gold/stock/real estate. This is because they no longer believe in cryptocurrency and they think Bitcoin is same to other coins that scammed them.

We may not have so many shops that are accepting cryptocurrency as payment, and the reason for this is because in most countries government haven't fully accept cryptocurrency and many people don't want to link cryptocurrency to their business because they are afraid and do not know what will be the consequences.
Though i haven't been to every country,  but i will use my country to judge. Here we may not have shops, institutes that are accepting cryptocurrency, the government is not talking anything about cryptocurrency but I can say 70% of the young people are into cryptocurrency. I don't think people found cryptocurrency to be strange in my country.

Stories about altcoin investors who are successful in achieving large profits whose value can change lives are interesting stories for many people to get directly involved in crypto because they want to experience the same success but also failures are stories that are also scattered around but usually people will focus more on success stories. that's why more and more people are getting to know cryptocurrency and after experiencing it first hand they will slowly start to get to know Bitcoin and realize that even though altcoins provide more open opportunities for big profits but storing Bitcoin is much safer, so yes the many projects that fail bring more people to know about crypto even though that is the worst part of cryptocurrency, because project failure is part of the scam in the crypto world.

This is not entirely true in my opinion. Failed crypto projects only promote Bitcoin to those who have not given up after incurring losses. Many people condemn cryptocurrency, Bitcoin inclusive,  after the lose money through scam. It is only those who are able to do some findings and discover that not all cryptocurrencies are bad, that happens to stick to Bitcoin knowing that it is different from the rest.

Some people I started with have shifted from Bitcoin to other areas siting risk and scam that are prevalent in cryptocurrency. If you actually know how many scams some of us suffer in this journey, then you will understand why they took those decisions.

So while failed projects created strong Bitcoin believers,
they actually scared a lot of people away from Bitcoin.

What OP said would have been totally true assuming when projects fail, new ones don't emanate. If it happens so, it will mean that for each failed project, the participants will return to bitcoin until the very last project. But this is different from the reality. In reality, as many projects are failing, more are being launched and this enable people to jump from the one that has failed today to the one that will fail tomorrow and the cycle continues.

Only a few will embrace only bitcoin or have the larger percentage of their portfolio in bitcoin while using the rest to gamble in altcoins.

Everyone has their own vision, if we look at what you are seeing this is clearly benefiting bitcoin. But there are also some other people who think that because there are so many scam projects created and that has caused many people to misunderstand that bitcoin is also one of them, and that is why many people call Bitcoin a scam. 

Having many altcoin projects helps the market become more diverse and competitive, thereby giving investors more choices. But with many projects created but not strictly regulated, it leaves the market rife with scams and gives the cryptocurrency industry a bad reputation. So, it's hard to say that the failure of altcoin projects is a good thing for bitcoin.