I think Pitt doesn't get as much credit because of his looks, tbh. People don't think you can be both at once or are going to be very begrudging about it.
Look at Mcconaughhey, when he finally stopped getting cast in those romantic comedys, etc. which Hollywood confined him to based on his looks he has shown to be an excellent actor in a lot of his newer movies.
Pitt got those opportunities while being younger but still believe people hold his looks against him in their opinions of his acting skills.