You say that about Maupay, but we signed him for £1.6m(?) in 2017, he scored 37 goals in 85 Championship games then we sold him to Brighton 2 years later for around £20m. While he was popular around the club and a good trainer etc.
The point being that since we've come into PL money etc, we've moved on from that sort of signing - eg signing Kevin Schade, a 22 y.o. German international striker for £22m last June after a six month loan. Problem was Schade got a very bad long term injury soon after (made his return off the bench against you), at the same time as Toney was serving his 8 month ban.
Therefore Maupay was just a quick, temporary fix on loan from Everton, who we knew would fit in immediately. And with 6 PL goals already, he's done his bit (whilst also being the leading PL scorer on Everton's books this season!). We probably won't sign him again permanently, but if we do, it will purely as a squad player and because he'll be cheap, as Everton look to reduce costs desperately.
Btw, I seem to recall that Sheff U were in for Maupay at the time he went to Brighton, but signed McBurnie instead for something similar. I'm not sure that you got better value for money, though you may disagree.