Basically I'm questioning the commenter's claim that they kept trying to get their hands on a 10-series, then 20-series, then 30-series card before giving up. They must not have tried at all in 2019.
* There's always new product releasing in the future, and the hardware you buy will inevitably depreciate. If you can get value from buying now and using now, then it's not worth waiting. If you can't, then you didn't have to buy in the first place.
* Futhermore, new product releases are staggered. Taking the RX 6000 series as an example, the high-end 6800 XT and 6900 XT released several months before the 6700 XT, and the 6600 XT came a few months after that.
Why? More future proof interfaces. DDR5, PCIe 5, AM5(?) etc.
It sound like you're in the second category, then. If you really belong there, that's fine.
But honestly, I got a DDR3 machine towards the end of DDR3's lifecycle, and I have no regrets. I used the CPU/Mobo/RAM for more than 5 years, and by the time I upgraded, DDR4 got fast and cheap enough where I felt I got my money's worth from both my initial purchase and my upgrade.