I don’t think they’re really any harder to find than quality defensive linemen. It’s just that now with many teams playing 3-4 defense, you need lesser numbers of them. I always felt that it was too difficult to find enough quality defensive linemen to play a 4-3 defense.
I’m not even sure how the term “quality” is defined in the context of this discussion.
I disagree. On a couple of levels. For one, I don't think the prevalence of 3-4 teams make a difference. Nickel is the base defense, league wide. Essentially all teams need two edge types and two interior types to play starting snaps and then depth behind them. That's true of all teams, regardless of whether their actual "base" is 3-4 or 4-3.
And then secondly, you see more teams around the league hamstrung by offensive line woes than nearly any other position but QB. There have been several Chargers teams that were undercut by terrible OL play. The Broncos of recent history had the same problem. The Seahawks are a notable example, as were their division mates the Rams before last season, and now the Cardinals are in that same spot. The Lions have dealt with serious OL problems for years, and it's also the main weakness of a strong Vikings roster. The Bengals season was essentially sunk by their OL last year. The Bills' OL is currently an abomination. The interior OL of the Dolphins has been dreadful forever. The Giants had to spend crazy money on an average tackle this offseason because their pass pro was so bad. The Texans' offensive line is a disaster. The Colts' line got their all-world QB laid up for two years. The Panthers spent real money on Matt freaking Kalil to try and address their tackle position.
I think the contracts getting handed out demonstrate how badly teams are needing quality OL. Andrew Norwell just got 5/67.5/30 to play guard. Just three years ago, top FA guards were getting 7-8M (e.g. Orlando Franklin in 2015- 5/36.5). Now they're getting over 13M. That's an 87% increase, despite the cap only rising 24% over that same time frame. In 2014, Branden Albert-- a solid, but unspectacular left tackle-- got 9.4 per on a 5 year deals. Nate Solder just got 15.5M per-- a 65% increase over a span where the cap only increased by 33%.
I think Packer fans are a little insulated from this trend. For whatever faults he had, TT was a master at finding quality OL in the middle rounds with consistency. James Campen deserves credit too. It's the single biggest competitive advantage Green Bay has had outside of Rodgers. But it doesn't change the realty that OL play is a major issue league wide.