You can't expect them to support every single product they've ever released forever. And they're still doing better than AMD in that regard.
If nvidia had the pre-GSP cards' drivers opensourced at least there would be a chance of maintaining support. But nvidia pulled the plug.
Intel's and AMD's drivers in the Mesa project will continue to receive support.
For example, just this week: Phoronix: Linux 6.19's Significant ~30% Performance Boost For Old AMD Radeon GPUs These are GCN1 GPUs from 13yrs ago.