We have Irvin, Suarez and Romero in AAA this season, why would we give Happ three years when one of them is highly likely to be a better pitcher in 2021. It's not like Happ is a game changer, he's a LH version of what we already have in the rotation - FIP 3.98, 3.76, 3.96 last three seasons.
Philly FIP last season: Nola 3.01, Pivetta 3.80, Velasquez 3.75, Eflin 3.80, Arrieta 4.26
Eickhoff (2 previous seasons): 4.19, 4.30
Ray last four years: 4.32, 3.72, 3.76, 3.53 (downhill trend is concerning)
Point is adding a 3.80 - 4.00 guy isn't worth real assets or an overpay, whether it's Ray or Happ.
Which is why McCutchen at three years makes more sense than Happ for three years, he's an immediate upgrade on offense and defense, strong clubhouse presence, highly durable, and even if he declines, will be a valuable bench piece in the 3rd year of his deal.
If we can't sign Harper/Machado, then the best move isn't a middle of the rotation starter but another OF or a 3B who's better defensively than Franco. If you want to improve the pitching, keep improving the defense.