It's not a shame, to support old GPUs devs have to work and put time and efforts to miner work with old gpus.
I don't have numbers, but old GPUs before RX Polaris and Nvidia series 1XXX must be minimum, and doesn't worth to support anymore, can you imagine to work hard to support these gpus, and only a few miners still have one of these?
Do you still have 6970 and 7970?
I'd love to see, post some pictures here
And these cards still have some value
I have a 7970 xfx card. blower style.