Cavani signing a new contract with PSG was an unfortunate development from United's perspective, IMO. Given the paucity of good striker options (in, or close to their peak productivity years) in the market, he would have been an exceptional Bosman acquisition in 2018 (considering that someone like Higuaín - who's at a comparable level, went €90 million). Cavani works hard, has a clean fitness record with only
12 games missed since 2011 because of injury related issues, scored 49 goals in 50 games (including 1 GPG in the Champions League), is technically decent with good physicality, and quite seasoned at this stage of his career - kind of the ideal Mourinho striker. You could then hold off on another striker transfer for a couple years, or maybe sign someone like Dolberg (more complete than Belotti) or Silva (comparable to Morata in terms of skillset) and loan them out (or back to Ajax/Porto) for experience, or employ a wait and observe approach with our own Rashford - who would be 22/23 when Cavani's 34 - so you'd have a better idea of his standing as a long term #9. Mourinho looks for specific traits in his striker, and there aren't a lot of good options in a market that's already shallow in terms of
realistic quality.