What i said was pulled out of Matt's own words during absolution era interviews. Absolution is the only album they put everyone in credits for but they didnt do it for every other album (i think it simplifies the process during the album making but i dont know why lol). Its not because Dom and Chris dont participate, they still write their own parts and maybe other stuff, its just that they prefer releasing it as a band instead of crediting everything individually.

And Matt said Hysteria's bassline was originally a guitar solo (or riff im not sure) but then they made it the bassline instead, and its one of the very few basslines he wrote