Has NFL Become A Mediocre League?

After watching this season, well the last few seasons there is only one team that has been consistently good, the New England Patriots. Other than that the league is wide open, the way the hierarchy intended. I don't know whether the talent is diluted due to the size of the league, the salary cap and free agency, or a combination. The play at times seems sloppy with bad technique blocking, tackling, and especially pass catching. I believe that's why one player makes such a difference.

I don't see the caliber of play, I'm not talking intensity, that I saw thru the mid 70's. The execution isn't the same. Any thoughts?