I love how altcoins and Bitcoin moved forward in 2017. A terrible profit margin was made when Domain BTC.D dropped from over 80% to around 50%. That has led altcoins to increase in capitalization one by one. At that time, there were not as many altcoin projects as there are now.
Currently, there are about 10,000 altcoins, so the ability to create a strong mass increase like in 2017 is more difficult, not to mention that the BTC.D domain is below 50%.
There are a lot of altcoins since 2017, alts is created everydays but most of them are ended becoming a trash tokens. So i think the more alts in the market is not going to affect the price growth of an alts. Investors are only hooked up on a good alts, aw we can see this year there are a lot of alts having price increase more than 10x times in short time, that means if the alts is really good, no matter how many alts out there, it won't stop the growth.
Now it's the challenge for us as an investor to choose which alts to invest
We have more serious projects with investment from many big institutions like Coinbase, Binance Labs, Samsung... They are big corporations. They are strongly promoting the development of the cryptocurrency market.
Choosing an investment project is a good question. I will prioritize projects that are blockchain platforms because they can add value like how Solana, BSC did.