They also don't give artists enough time. John Blanche was given three months to paint this, for example:

It's not even cover art. Just something tossed into the 3rd. Edition rulebook.
Nowadays? Magic artists get a 6 week deadline. And they get roughly $1k per piece. To make a modest $4,000 per month, you have to crank out a new painting each week. And like you said, then there's the corporate approval where a committee nitpicks everything into compliance. Copyright shit doesn't help either.
And you just know these companies will switch to AI slop once they think they can get away with it.
