>>723728376
>the literal other half of this entire army is in 30K, what the fuck is this shit
Like I said, GW despises cross-compatibility.
Each GW game (40k, AoS, 30k, Fantasy) is split into separate teams. Each team logs the sales of their own game, regardless of what game the models are actually used for. Budget and bonuses naturally are allocated more to the teams that perform the best.
The 40k team knows that 30k Mechanicum would make great minis for 40k, but that would mean 30k would see more sales while 40k AdMech would potentially sell less, so the 40k team not only doesn't make rules for 30k Mechanicum, it specifically tries to avoid making units that 30k models could be used as stand-ins for.
It's why 30k tanks look different and often have different footprints; 30k Land Raiders aren't even sold any more in favor of the 30k-only Spartan Assault Tank. 30k Marine characters often come on 32mm bases, while 40k counterparts come on 40mm bases to try and dissuade from double-dipping.
GW manages to succeed IN SPITE of their practices, not because of them.
>>723728657
Custodes are an odd case because they're genuinely unpopular. In 30k they were a black sheep faction because most of their vehicles and heavy options were absurdly priced Resin that didn't sell. GW opted to then bring Custodes to 40k with minimal changes to try and sell more of aforementioned overpriced Resin.
Now Custodes are liable to be getting a 30k-only refresh, which is unlikely to translate to 40k.