Accumulating BTC gradually is not affordable for everyone, but it's quite affordable overall. Bitcoin transaction fee is normally very low, but again, even $0.3 is not nothing in some countries, for some people. Moreover, you do need to be able to save up and also afford to lose your savings when you're accumulating Bitcoin, so those who can barely make ends meet are also unable to go down that road. Finally, while I do agree that a bit of BTC is better than no BTC, it can be quite insignificant if you have a very small amount. For example, if over 1 year, you accumulate $200 of BTC, then even if BTC costs over $1 million, it's just $2k for you. And sure, it's not nothing, but there are very few cases in which this amount of money can be truly life-changing.
Accumulating bitcoin intensively is not affordable for everyone but doing this gradually (but not intensively) is affordable. They don't have to force themselves to invest money in bitcoin and only need to do accumulation anytime they have good finance and are ready for purchasing bitcoin.
So it is possible and doable for everyone to DCA bitcoin over a long time in gradual investment way.They don't need to be rich, gave too much money for accumulation over time.
It is hard and even impossible with many people to invest $5,000 in Bitcoin immediately but if they can do it gradually with time, their portfolio value will reach $5,000 quite easily.