I'll grant you the first one was watchable, fun even (but certainly no masterpiece) while each subsequent entry tried to outdo its predecessors in the "unrelentingly awful" category.
It's unclear why those involved with the franchise decided to totally abandoned the storylines and character arcs from the games to go in baffling directions, but needless to say it never worked out for the better.
There's one moment in particular I'll never forget from this series. Sitting there drinking with some friends, we're all staring in slack-jawed awe at the nonsense assaulting our eyes as a flock of very badly rendered CGI ravens attacked a post-apocalyptic convoy in Resident Evil: Extinction. The Birds somehow invaded Resident Evil, and it was even worse than I could have imagined.
I didn't even bother with any of the films past that point, and based on the review scores they garnered, it seems like I made the right life decision there.