Give up bitcoin's technical development? I still see bitcoin's source code is updated regularly.
We need to see that bitcoin is hard to innovate, but I believe it will soon adopt something to be the top currency as people expect it to be paid daily.
I only noticed that bitcoin investors were impatient when bitcoin dropped and they quickly left. As always, there are sellers, there will be buyers.
Bitcoin is at a pretty good price point and is stable for many days. I don't think bitcoin will depreciate in the future.

Im sure that a lot of people or investors in bitcoin still believed that the time will come when the bitcoin market price is going to reach and surpass its ATH.

The numbers of bitcoin holders continue to increase over the past years if you're going to check the statistics, so I don't think people are losing hope in bitcoin as there are still a lot of investors that until today is holding their bitcoin believing that bitcoin is going to surpass its ATH soon. The hype in bitcoin is gonna go up and down depending on the market value of it so its already expected, every news about it could affect the value a lot.

In a lot of cases, we cannot really blame all of the people who sell their bitcoin investment earlier since the world is experiencing a pandemic and a lot of people do not have a job, people need money so that they could buy food for their family. If your aiming for a high profit it would need long-term investment and most of the time its not worth it to hold on to your bitcoin if you're really in an emergency situation, not every people can invest and sustain their need without thinking about their investment for a long time. A lot of investors are always watching their investment for a possible sell for even a small profit will be enough.

first, you should add links to the post that you are talking about. so, we won't be misled about this topic.

IMO, most bitcoin early adopter who indirectly involved with bitcoin development already made their own path.
they made their own crypto, startup, or other blockchain company. so, maybe it makes people think that bitcoin development is too slow.

but,

let say on this forum.
we regularly saw a new bitcoin project from a company or just a community project.
not to mention the crypto gambling site that launched and always promoting their service regularly on this forum.
it just a little example of bitcoin development as an actual currency (in general).

It is usual to see people losing interest on something over time especially if their expectation is not met.  Others just simply gone tired and out of no reason give up on thing they used to be their interest.  As of the sell-off, it is a natural occurrence for Bitcoin and other cryptocurrencies.  Every trader wanted to take profit so whenever they see an opportunity to sell during surge, they will do it without hesitation.  This has been the cycle of anything in the market and Bitcoin is not an exemption.

People who give up on Bitcoin are usually those who have HODL Bitcoin for a long time, without being able to get the desired profit.
To my knowledge most people view Bitcoin as just a digital asset, so they will sell their Bitcoin if they have managed to get a profit.
Then some people don't believe Bitcoin will become a currency like it's fiat, because indeed some countries prohibit Bitcoin as payment.
Moreover, the number of merchants who accept Bitcoin as payment is still very small in number, that's why make many people have
given up on Bitcoin to become actual currency.

If they don't get their "desired" profit, then they haven't been holding it for long enough. I though those who were doing holding for short term and made a loss were the once that gave up on bitcoin and started to call it scam/ponzie scheme.
Well some do see it as a digit assets, but there are people that see it as a "currency" and use it for their daily transaction. The number of "physical" merchants that accept bitcoin is low, but there are tons of online shops that accepts bitcoin as a form of payment!

You cannot blame the investor for that, if they think that the technical development is slowing down to actually view it as a currency you cannot blame them and you will see many investors booking their profit during the next surge. Even in the past few months there are institutional investments investing heavily into bitcoin thinking that they could profit from the next rally and if every big investors have this idea i always wonder how deep the crash could be after the rally.

Despite all these you will see all these investors coming back once again expecting once again for a rally and it is going to be a cyclic process .

Depends on what kind of surge was that  . I don't know the meaning of surge so I Google it and found out that surge can also be a fall and not just rise  . If people buy in a fall surge , they are doing right and they haven't loose but there are also people that can still manage their investment after they bought on an upward surge . technical development of btc as a currency is slow moving and people got boreed of waiting so they don't expect too much anymore but this does not mean that they quit on holding a btc

I want to know that the laws of your country prohibit the possession of cryptocurrencies or prohibit the use of cryptocurrencies as currency.
China is a hostile country to cryptocurrencies but I have learned that they only prohibit the use of cryptocurrencies but they still allow people to own it as an asset.