I think that the biggest impact that ETFs have on Bitcoin is that it increased it's adoption, many people who were not comfortable with self custody embraced it. Also it helped build trust in Bitcoin, other people who were skeptical about Bitcoin became more trusting when institutional investors began to get in, they will reason that if this institutions have trust in Bitcoin they can too. Other than this assumptions Bitcoin was doing great before the ETFs were approved, it had already attained the reputation as a store of value. Overall I can say that ETFs made Bitcoin to be more attractive to both institutional and retail investors.

There are correlations of potential risk and profit.

Years ago, there was more and higher risk than now but there was also chances for better ROIs than now. When Bitcoin is older, it gets more matured, and its adoption become better as well as its market cap is bigger, all these things mean that Bitcoin gives people a safer investment option than years ago, and consequently its potential ROI for investment is smaller.

I don't advice any people to switch their interest from Bitcoin to shitcoins but let me use this chance to talk about another common mistake. People who are late comers in this market, usually ignore Bitcoin and choose altcoins, because they see altcoins are cheaper in price and have better potential ROIs. Life is not easy as that, and they lose money to shitcoins or meme tokens.