How is it irrelevant? You've contradicted yourself, as Leicester were league winners doing what got Barnsley relegated. Sunderland have signed almost exclusively under 23 players, and again, will likely make the play offs. Personally they would probably make the top 2, if the League wasn't so strong at the top end this year, and had they backed the manager with a capable striker. Haven't the bulk of Ipswich's signings over the past few years been under 23 players?
What you don't see with the promoted sides from this League, at least not very often, is signing low end ageing Championship players, and then getting promotion. If will never be the most common way to get out of this League, especially in the modern game. Weren't Brentford a great example too, of signing young players, especially from abroad and the lower leagues, and selling them for big money, like Watkins for example?
This is why I will defend Lowe. Until the Club changes their model, it doesn't matter who sits in his seat, there's nobody who's going to take this club forwards. You could bring Pep in, but you're not going to get any improvement if you're signing players who can't improve, and aren't capable to challenge the top 6. He's doing a great job, and if you want to criticize, I think you're targeting the wrong bloke.