Emphasis on dinosaur. His scheme worked in the 90's and 00's, but offenses have caught up to it and Lovie hasn't adapted.
Not even so much offenses as the rules.
You basically can't get a solid hit on a QB anymore unless someone comes free off the snap, which is never going to be the case if you don't blitz. And a zone scheme predicated on players spread across the field rapidly shrinking the windows into which the ball can be thrown as the play develops are inherently very high risk for targeting penalties, or mistakes made trying to avoid targeting penalties.
RPO stuff makes it more difficult too, but personnel can fix that, you just need more guys in the box with DB-type mobility. And RPO's are challenging to any defensive scheme, not just Lovie's.
All of that said, it can still work and don't be shocked if things go better for him in Houston than you're expecting.
I was there. He shredded us. I think the Bears GMs must have been at that game as well to draft him over Lamar Jackson.
Wrong draft, Lamar was the next year.
Patrick Mahomes is on a path to go down as one of the best players to ever put on a helmet, so the legend will probably be that he's the guy the Bears "should" have taken. But Mahomes was a wild, raw talent coming out of Texas Tech, and got to enter a perfect developmental environment sitting behind Alex Smith and learning from Andy Reid, I really do think that story might have turned out differently if he'd walked into the Bears mess.
It's Trubisky over Deshaun Watson that drives me nuts. Watson was as ready for the NFL as a college QB possibly can be, and in addition to his considerable talent, the way he had elevated a Clemson program that had a decades long reputation for underachievement before he walked in the door just screamed that this was the right guy for the challenge of being the Bears QB. And he still is. Trade anything that isn't nailed down to get that guy if the Texans are dumb enough to do it.