But then again, Mengi is nowhere close to having made the impact that Greenwood has made. But that's not the point, and its very unfair to Mengi.
Its not about who is a proven player, its about competition for places. We have so many young academy prospects, who are always touted to become the next big thing, but they rarely make it. There was so much hype about Gomes, Chong etc yet we saw how they are playing in the first team. But then we also have to look at Williams or Greenwood. So its up in the air.
We had Smalling and Evans as backup to Rio and Vida, when we went ahead and bought Jones for a very high fee. Competition is always good. We saw how much Maguire had to play this season. I think Badiashile is a talented young CB(who I have never seen play tbf, just going on reputation here), who can compete with Tuanzebe and Bailly for a spot. Mengi can go on a loan like Tuanzebe/TFM did and prove himself.
Its upto the scouting team to determine which young player to take a gamble on. If we had the same mentality we could have though "hey why buy this Christiano guy, we see some new flashy winger every year", we might have missed out. And maybe we should have HAD that kind of thinking when we went for Bebe/Obertan/Depay.
So its always a gamble.