Sure, I'd still go see them live to hear the old songs, but like Suffocation, Slayer, et al., their days of making relevant albums seem done.
While everything you say is true, there's a possibility they'll pull it off.
The problem is really intent: when the goal is to gratify a captured audience, one doesn't rock the boat.
If you have 1,000,000 people who will pay $15 to hear Pantera with jazzy solos, and 100,000 who will pay $15 to hear ripping, emotionally-challenging, awkward-mortality-moment-inducing death metal, and you've already made 5 albums for the million fools, why not keep making albums for fools?
If you don't, your label will drop you and you will possibly have legal battles and trouble keeping your band together as band members flake out for the easy $68,000/year jobs managing Walgreenses.