He's obviously not nearly the defender Davis is though. Not sure if that's just a focus / effort issue or something more. Towns was expected to be a very good defensive anchor when he came into the league.
But that's the issue, while they have similar offensive value one is an elite defensive C and the other is clearly a bad defensive C. Given how much important team defense is at the C position I don't think I would want to sell the farm for Towns.
He just doesn't show consistent effort at that end for more than a month a year.
How much of that is his team? He has the best DRTG on the Wolves (tied with Covington). Covington is the only + defender on the entire team. I do wonder if Towns was a team that wasn't a sieve in the backcourt how his defense might actually look. I mean Covington was a DPOY contender last year and looks fairly average this year because the team as a whole is filled with awful defenders. Get Towns away from Wiggins and company, and I'm not so sure he doesn't become a + defender (not elite, but certainly better than average). He has all of the physical tools and has solid steal and shot blocking numbers, which shows his instincts, timing, and soft hands. Put Towns on a good defensive team and I think his defensive liability disappears into a cloud of dust.
^this. I don't confuse him for a great (or even good) defender, but his defence is clearly at least passable for an NBA team looking to compete. Obviously there's more to defence than what Moranis posted (individual DRTG and raw stock numbers are awful defensive metrics), but Towns passes the eye test and isn't anything really bad in play tracking statistics (RAPTOR is still kind of a meme at this point but it still gives you some valuable information).
I dunno about your eye test, but Towns is in general rather lazy, in the wrong position, and just plan slow on defense. That's what I see when I watch the Wolves.
The numbers back it up over the course of his career he's been a negative defensive impact player, despite his excellent physical tools.
He's good enough on offense to compete with him on your team, but having a C who doesn't player adequate team defense is a huge problem to overcome in the playoffs when you're facing the best teams who have great players to attack him.