Football has progressed then. The full back role has been the biggest contributor from a positional standpoint. Now a "modern full back" is expected to show consistency in attack and defence, which is why Dalot wouldn't get a spot in most top teams, or top 4 teams. Tomiyasu has shown more chops than Dalot has, TAA is obviously miles better, James is better, Walker is better, Cancelo is better, heck further down the list Ricardo Periera is better, Semedo this season has been better, Coufal/Johnson are better.
Dalot has been an improvement on Wan Bissaka, I never expected that. He's been able to do a job relatively solid without being too careless on the ball. But his value offensively is non existent and has no place as a starter in the long term in that regard.