Its a good thing that you had end up earning huge amount of bitcoin at the present without using your fiat to start it all. I think there are a lot here that are paid in bitcoin from their own jobs or skills in crypto and by keeping and hodling them in their wallet, they end up having a huge amount in years. So its not just through fiat that we can make investments in bitcoin, we can also earn from it from our own hardworks and expertise that our clients are ending up paying or rewarding us with bitcoin.

Well, if this is bout using $ to buy Bitcoin directly, yeah maybe there are. I ma one of those who  never deposit any $ to buy Bitcoin directly.
But, if this is about the entire investment, I think that even we don't deposit any $, it doesn't mean that we don't invest any single $.
Even I got the rewards in Bitcoin from signature campaigns so far, I am still investing:
- My time
- my energy and thought
- and also my money to buy internet connection and also others.
So, it is no exact free investment entirely.
Even we may be do faucet or other free programs to get Mbtc, we should still spend something

the first time I tried to invest, I used little capital and bought cheap crypto. then after that I also followed several bounties to get paid and from that payment I collected to buy bitcoins. even though the bitcoins that I bought from the bounty payment were not much but at least I have bitcoin assets. The more I come here, the more I follow the bounty too and my assets are also increasing from the profits that I get while investing. it really helped my economy, but now I'm more focused on trading and I also invest some coins. I hope I can get a bigger profit.

I see a contradiction. Calling people who know about bitcoin does not mean that they are, as you call them, "bitcoiners", that is, bitcoin fans.
I would call people "bitcoiners", those people who sincerely believe in bitcoin, invest in it by spending their money in fiat, or even make money on the forum, but do not immediately run to cash it out. These people are holders who are not bothered by volatility, whether it is falling or, on the contrary, rising. These are the people affected by the Bitcoin religion. Everyone who simply earns bitcoin and quickly exchanges it for fiat for their vital needs is ordinary people who need to earn at any cost. They do not care what and what currency will be paid for their work.
On the contrary, I met here people who do not see any alternative for their financial freedom other than bitcoin. These people can be called bitcoin fans, and I consider them to be real bitcoiners.

I don not really know why you have come to that conclusion and how you verified that information, but I find it hard to believe that quite a lot of people haven't invested in the network they have been in for a long time, if you say newcomers, then I can agree with you; but then there could be quite a few reasons why someone wouldn't invest in Bitcoin even if they believe in it, they could prolly not have the funds to do so, or maybe they are still at a stage were they are trying to understand the network properly before putting their funds in it, or they could be worried about it's volatility and are always waiting for a comfortable time to buy, but they never get a good chance, etc.

Mind you that people may not actually buy Bitcoin with fiat, but earn it through other means and as such they have invested in the network, you must not have bought with fiat for it to be called an "investment", if for example you're earning BTC through one service or the other you render and hodling it, then you definitely are a Bitcoin investor.