I find it highly amusing when people ignore Godwin's actual role with the Bucs this past season, and just blythely assume that acceptable substitutes are just lying around the ground like rocks on a New Hampshire mountainside. They ignore that, even with the addition of AB, Godwin caught passes on an 87 reception pace. So let me try to translate Godwin to the Patriots, again, in the hopes of it becoming more clear:
Evans is Moss
Godwin is Welker
And it's not about actual "worth". Almost without exception, neither the franchise tag nor day one free agency is about actual "worth". If AB could be counted on for all of 2021, the equation would be different, but you cannot have AB as a required, top 2 WR, piece on your team. He has to be a bonus player.
So you need a Welker to replace the Bucs' Welker (Godwin), and there sure as hell are not a plethora of them available in FA this year.
Edit: I forgot to note the following, but it's a big part of the point:
Chris Godwin first downs:
2018: 48
2019: 63 (in 14 games)
2020: 43 (on pace for 57 in a full season)