Why not buy a new card instead of hassle with outdated hardware and make a problem of not supporting a device that even nvidia dropped long long time ago.
Do keep in mind that a lot of us have EXISTING hardware on hand we'd like to mine more efficiently with, and don't see any reason to toss out working hardware just to spend $$$ on new stuff.
There are also the SMALL miners that can't afford to casually just "buy a new card".
Also keep in mind that AMD in particular had *3 generations* of "new" stuff that was no more than a bios refresh + slightly faster RAM with NO CHANGE TO THE ACTUAL GPU for most of the cards in the "new" line.
(HD 7750/7770/78xx/79xx series, R5/7/9 2xx series, R5/7/9 3xx series - each generation only added 1 or 2 actual NEW gpu chips, usually at the top-end of the new line).
Some of the R9 3xx series IS STILL IN PRODUCTION as AMD hasn't released their RX 4xx series replacements yet - which makes cards like the HD 7970 and 7950 arguably still current, and DEFINITELY the HD 7990.
They also haven't released replacements for the bottom-end cards, so my HD 7750 is arguably still a CURRENT GPU (not one a miner should go out to buy, but since I have them on hand already no point in not USING them and achieving even MORE profit past the ROI they managed years ago).
As far as the GPU goes, my HD 7870 is in actual FACT only one generation behind current, even if it's OFFICIALLY 4 generations old and 3-4 years out of production - and my R9 290s blow away ANY RX SERIES CARD that has been released to date on hashrate on pretty much ANY coin despite having been "dropped years ago".