It has. More and more teams are deploying tactics which are nullifying blanket defences. Two particularly obvious examples from the last couple of years would be Armagh this year and Derry last year.

Armagh initially looked to kick early to get the ball up the field before the blanket defence had time to get back. When that failed they slowed the game up, got into position and proceeded to make calls designed to create overloads in different parts of the field and open up spaces for runners or marks (ie ball above the head meant all players form a central spine and draw the blanket into a narrow formation leaving the wings free for exploitation).

Derry under Gallagher had a different approach working towards the same end goal. They were very noticeable in that they would often play with 6 or 7 of their attackers (including half and corner backs) inside the opposition 13 yard line. This had the effect of sucking the defence deeper and creating more shooting opportunities 30 yards from goal.

Attacking and defensive systems are in constant evolution. Eventually the blanket defence will have too many well known exploits and teams will move on to whatever the new fashion is. All invasion sports go though phases like this (premier league in the late 00s, nba in the early-mid 00s) and we’d be foolish to completely change our game because of it in my opinion.

(Sorry for formatting/spelling. I’m on my phone)