It is currently just above $200 billion from the data on CMC. I personally don't think it will happen but with the volatility of the cryptocurrency market, yes there is a possibility that BTC may reach $500 billion this year.   

This rewarding users for watching annoying ads is becoming a thing now. It all started with Basic Attention Token if I am not mistaken but you have to do it through the brave browser. Verasity on the other hand doesn't need a specific browser. There is also this new project called Honeypod, a project focused on privacy but also allows you to earn crypto by allowing ads of your choice.

This is nice. I believe this is what many of the regular participants in token sales is looking for.

Do you think the ICOs will bring their popularity back with the current price increase of cryptocurrencies?

The timing of these news regarding ICO regulations could not have been any better. So yes, it is likely that investors will go back to (regulated) ICOs.

I see there is a low interest on new altcoins currently, especially new altcoins from ICO projects.

You have to take into consideration the condition of the market when the new altcoins came out. Many investors are still pessimistic since a lot of them got rekt from joining the ICO craze back in 2017.

I wonder if there will be no good new altcoins anymore it this condition continues.
No projects can survive without supports from investors.

Despite existing for a few years now, the crypto market is still relatively young. New altcoins will continue to come out and some investors will still be willing to invest in projects of their own choice.

We can say it's for money, I think that's an obvious answer. We also have to remember that one reason these altcoins came out is because of the speed and scalability issue of bitcoin. Seriously, do you really think people will use bitcoin who takes minutes or hours when the network is highly congested just to pay a $10 item (or less)? 

I think there are too many projects on the ethereum blockchain that are clogging the network and the disintegrations may be advantageous. I expect new blockchain projects to keep on coming and they will probably choose ethereum also, so those projects moving out will help ease the network.

Of course they can, they have all the resources they need. Many Chinese citizens are already fine with the digital currencies and they probably would not mind using a stable coin supported by their government. The question is, will it be accepted in many other countries?