They break. I have a GT730 card which came with my office PC. This card’s support has ended with the 470 driver series, which is one of last (if not the last) release for the previous generation of NVIDIA drivers.
Now, the drivers still ship, and the kernel module is still maintained, but the surrounding GLX drivers are static. As the desktop Linux improves and moves forward, accelerated stuff tends to get migrated to newer technologies, or its GLX use is getting refined. This causes drivers to lose compatibility over time.
This means more and more of your applications fail to start or break in mysterious ways. Also there’s Wayland support issue, which is the elephant in the room.
I had to buy an AMD card which works better, because all the software ecosystem around that card is maintained by volunteers, and the card is architected for working with open drivers well. AMD redesigned its silicon to allow open drivers to work with every unit on the GPU without revealing sensitive information (like HDCP keys) while allowing open drivers to access video encoders and such on the card.
After I got that card, all my problems have just vanished.
So, I’ll never use an NVIDIA card on my computer for the foreseeable future.