Ronaldo case is different, right from his first game he looked class. Even before he stepped up to different class in 2006-07, it was always hard to sign a better winger than Ronaldo in that 2004-06 time, he was very good player and regular for Portugal NT too. Same with Rooney, even though he was 18 when we signed him, it was hard to sign a better striker than Rooney in that period. Both were already very good players and we had to pay huge money to sign better players than them.
Amad case is different, he is very much unknown entity at top level, we can't create a road map for next 3 years with unknown entities, especially when making top 4 is such a struggle these days. I believe he will be top player but that's my opinion and I have nothing to lose with that opinion, the people who have so much to lose might not take the risk on such a young player.
Regarding Rashford, we signed Mkhi, Sanchez as wingers, we signed Lukaku when Zlatan was injured. It blocked both Rashford and Martial's development but we did it as at that time it was important to sign a 9 and also player who were ready (or proven) to play week in week out (without benefit of hindsight btw).
IMO we deviated from what made us so good in the last few years, we never relied on young players alone, we always had the mix of young players, peak players and very experienced players. When we had Ronaldo and Rooney as teenagers (Rooney as a teenager was already a sensation anyways) we also had players like RVN, Giggs, Scholes who all were good attackers. Before that when players like Scholes, Beckham broke through, we had players like Cantona, Keane, Dane and few other great players.
Sancho doesn't fit in the peak players or in the experienced players category but he is already one of the top wingers in Europe. We need to improve our wing position and we are about to do that. Amad will get his chances and if he shows he is capable of stepping up then we will have good numbers to rotate. City have players like Sterling, Foden, KdB, B.Silva, Mahrez and they all play good enough number of games. People said same thing about Foden, how he isn't getting chances or how his development is stalled but now he looks ready. Competition for places or playing alongside very good players helped him to develop too and also training with good players.
Also not sure about Cavani and Greenwood. I don't think Ole thinks Greenwood is ready for CF position, he played almost 95% of his games as RW, so Cavani deal shouldn't change anything. Also at this point, we don't even know whether Greenwood will end up as CF or RW.
The way I see, Rashford, Sancho, Greenwood, Amad is good enough numbers for wing position, we have Sancho, Rashford who plays in both wing position, Greenwood can play as RW and CF, Amad looked very much like a RW but going by his playing style, wouldn't be surprised if he ends up as AM or plays well as AM. He looks like proper playmaker. We are a big club and should always try to have the best possible squad + young players with great potential. We have lost our way going extremes in last few years.
Finally we are building a good squad and if players progress as we expect then there will be good competition for places. There will obviously a time where players won't be happy with playing time or don't want to be rotated, but we can always make decisions at that time.
don't tempt fate.
