Seat of my pants comment. Rockstar/Take Two got really butthurt over a certain type of mod tool around the release of gta v, specifically, tools that can open and modify “img” files, which are essentially large compilation files which hold all of the textures and geometry for models in the game. There’s one for vehicles, one for foliage, etc.
So, their course of action was to throw lawyers at it, and an injunction (or something) was filed against the developers and they were forced to stop development and remove it from the places it was available online for download.
Cue huge pushback from pc community for “killing” mod/3rd party development. I believe the biggest projects affected were those working on bringing older game maps into the newer engine, like bringing the gta:sa map into the gta v engine.
I forget what happened next, either the developers fought back and got the injunction revoked, or a fork (kind of like a clone) was developed and because of the pushback Rockstar /take two did not pursue the same course of action again. I wanna say it was a bit of both.
Of course, this is all conjecture. The later (IF ANY) Release date of RDR2 for pc is going to come down to a multitude of factors, such as:
Second stage development for pc and other platforms
Life cycle maturity benefits (see gta v)
And the one that has people worried, the fact that RDR has historically been a console only IP (such as midnight club later in life, for which, midnight club 3 and midnight club LA have never seen a PC release)