Will that list become...not so endless in the future as the value gets higher?
The question depends on how deep and wide crypto adoption is in the future. In the current history, we can say that bitcoin will be continuously adopted thus the demands and application of Bitcoin will increase. With that in the scenario, we can safely say that Buying Bitcoin via the different platforms will become easier. The reason behind the idea is that, when there is huge amount of demand, companies always take advantage of the possible venture they can create in order to have a profit in a trending and emerging industry.
It'll definitely get much easier to buy bitcoin over time. That's inevitable as Bitcoin continues to grow, more people adopt it, more companies want to make money by offering it, and it becomes more engrained in society. It's already very easy to buy now in free nations - like in the US you can easily go to a number of exchanges to buy, buy on Robinhood, cash app, PayPal, and more. Institutional investors have several options now as well.
Where it should get wayyy easier in the years to come is for the traditional stock market investor to buy through the same service they currently buy their stocks through (their brokerage account or whatever) and to buy Bitcoin anonymously. Buying Bitcoin anonymously now is relegated to a few sites where you end up paying a pretty markup on the price. In the future, as more people use Bitcoin, and as government try to react to Bitcoin's growth more by surveilling it to a greater degree, I'd like to see a lot better options for getting Bitcoin anonymously away from CEXs so that your every transaction is attempted to be tracked by crypto tracking companies and the govt.
It is your choice to move away from CEX and I think that isn't a bad idea, though you might find it difficult by that time when the government decided to be on-hand with crypto regulations. As the government gets involved with Bitcoin, I think that platform that offers anonymous buy and sell transaction will be forced to shutdown by the government in guise of anti-money laundering law. So I think CEX will have its golden day while DEX will be restricted.