Lot to unpack here.
And perhaps they would have not been annihilated had they not used inferior platforms
This is so patently untrue that I won't even bother.
And neither do they fit with Scorpions
Based on what criteria?
Actual criteria, not your personal opinion. What are the characteristics of the Scorpions that would preclude ProtoMechs from being a fit for them?
They did at first and later they ditched them because they didn't fit with their faction
No, they ditched them because their current writer personally dislikes them. (And again, this is not my opinion, this is something that said writer has said on these forums, and I believe in this very thread.)
Even when they did have them the whole project was second fiddle to Undine battle armor (a battle armor!)
Also untrue. The Undine was already in production by the time the Scorpions started designing their own Protos.
Jade Falcons also did buy in at first and later they ditched them because they were inferior platforms and because they didn't fit with their faction
That's not quite accurate. The Erinyes was a poorly-designed platform (and intentionally so, by the Society), and that's why the Falcons chose not to move forward with them.
Nova Cats did too... and then they didn't just like Falcons and Scorpions
The Nova Cats never used Protos. They were Abjured from the Homeworlds before the other Clans started getting their hands on Proto technology. I was incorrect here. Leaving it in since I can admit when I’m wrong.
I have no clue why some people insist on having Scorpions of all factions being saddled with protomechs
Because we like them. It's not complicated.
with lore that makes zero sense in-universe
Just because you don't like the lore doesn't mean it makes no sense.
and which resoundingly fail at doing the very thing they were supposedly created to do
I have a feeling that you've never actually used Protos at the gaming table, because if you had, you'd know this isn't the case.
And I can name several militaries in Battletech who do have issue with it because of the same waste-not-want-not values such as Ghost Bears, Wolves, Jade Falcons, Smoke Jaguars, Nova Cats or Sea Foxes
Care to guess what all those militaries have in common?
The fact that these other Clans aren't using Protos (which isn't solely attributed to what you're claiming; many don't use them because of the Society's connection to them, others don't use them because, again, TPTB have deemed it so arbitrarily) doesn't detract from the fact that the Clans that
do use them have gotten enough mileage out of them that they've not only made their own designs, but they've innovated with them: ultraheavies, quads, gliders, new ProtoMech equipment, even a new Phenotype in some cases.
Can you maybe come back with some actual facts and references? Your personal opinions aren't really something worth debating here. You don't like them, and have made that very clear. And it's ironic to me that, for someone who loves to tell people on these forums "read the books/Sarna" at every opportunity, you haven't actually read them yourself, because most of the above is simply not substantiated in the source material. I'm happy to have a civil debate with you (insofar as much as you refrain from the condescension and personal attacks), but I have no interest in debating personal opinions, I want to debate actual
facts. If you can't do that, I'm just going to ignore and/or block you again. Fair enough?