Games of the past were made with proper consideration of the hardware available at the time and its limitations, as well as considerations of the then-current market and cultural zeitgeist. Games like DOOM, for example, didn't come about in a vacuum. It was developed with the hardware available at the time, and out of considerations for previous games, to meet the needs of the gaming market at the time.
Modern-day retro-style games are made without consideration of hardware limitations or current trends, optimized far below what the developers of the day had to manage. Someone that makes a DOOM-inspired game hasn't made a retro game, they've just made gaming slop that crudely apes DOOM, wears the tag "retro" the same way a trans person wears the tag of "woman" and fooling no-one.