It wasn't sloppy hardware 8 years ago. It's old, it's mostly obsolete, and the driver for newer better hardware. Trying to squeeze anything out of it is a false economy.
150M consoles out there of which probably half haven't been switched on in man years. The lifetime sales numbers of old tech isnt an indicator of future sales of next gen games nor where sales figures are predicted from or planned for. That's naive to even considder.
The game is poorly optimised for ps4. Not surprising. Why put the effort in when it's not the target market?
The PS4 is clearly a target market since they tried to release Cyberpunk 2077 for it but has been pulled by Sony because it was buggy utter rubbish. That is a different scenario and not like they ignored it totally or they wouldn't have done it in the first place. They tried and messed up royally.
No one will develop a game since 2012 for target market of a next gex consoles that will have about 6M all up out in the wild when they launch.
From that, they will need also subset of owners that want to buy my game which might be 3M all up.
They better hope that they can make some $$$ out the PC market since the next gen console market is not going to do it now. Call it a courageous and ambitious business model which must have a very fat margin even if they delivered software without the undocumented 'features'.
The PS4's haven't suddenly been switched off and binned in droves yet - the PS5 only was released last month. It also has a huge back catalogue to explore and will be alive for some time yet. Even if you conservatively estimate that 80M are still powered on regularly then you still are ignoring 30 times or more of the present install base which is commercially stupid.
PS4 and PS5 are similar both use x86 architecture, AMD hardware and both use a variant of FreeBSD. Should not make any backport impossible.
Sure they will lose a load of graphic and gameplay detail which will be big hit and no doubt a factor of why it is so rubbish now but still should not be in the sorry alpha release 'compile with no errors and ship' state that it is presently in.