Currently, many investors in cryptocurrency invest funds precisely through exchanges such as Binance. But if there were none, would cryptocurrency be as popular as it is now and would it be so easy to buy?
I don't think cryptocurrencies would be so popular, but we would go back to doing exchanges purely like in the past, peer2peer exchanges only, in which we would also have to be extremely careful not to be scammed, today many platforms offer peer2peer exchanges, but there are not so popular.
If there were no crypto exchanges, the most likely alternative would be peer-to-peer transactions. People would directly trade cryptocurrencies with each other, potentially using platforms that connect buyers and sellers. While this method allows for decentralized trading, it might pose challenges in terms of liquidity, security, and transparency.
When crypto project is created, they will have their official website where interested people can buy. These crypto projects will also launch wallet for their native currencies, so you can hold in their respective wallets. However, with exchanges, and multi-currency wallets, I do not think crypto would be so popular.