On paper it's a simple question however why didn't United, Chelsea, City, Spurs or Arsenal or for that matter even Bayern, Juventus, PSG (best placed), Atletico, Barca or Real pick up Kante or Payet ?
The answer probably lies in they, like us, can only take so many gambles, sometimes they pay off others times they don't. We can't beat ourselves up for missing out on gems of that quality.
It's not really a valid comparison when all of those teams can buy and compete for the best players on the market. We can't, which is exactly why we should have the transfer nous and scouting set up to spot these sort of players. Those other teams don't necessarily need to, bar Atletico & Spurs, who arguably make these sort of purchases anyway.