The point is those are very different pathways. Developing pitching from within is obviously important, that's what the Brewers did with Hader and Williams, and also had positive knock on effects by being able to maximize lesser pitchers in lower leverage. Of recent Cubs vintage, Alzolay is the biggest Cubs success in that regard, and only for part of a season. Until very recently that was the toll being paid for not developing pitchers, why McLeod didn't survive the front office shake up, etc. Their improvements in that regard are starting to bear fruit, having already gotten 30+ excellent pen innings from Brown and Wesneski.
Unlocking something new in a mid-20s RP on his 2nd, 3rd, 4th organization is a different roster building pathway, that's what Hudson and Megill are, and what I'm talking about as a thing that happens in both directions to lots of teams. There's little indication the Cubs are net negative in that pathway, especially when talking about forward-facing given how recently they've turned Leiter Jr and Merryweather into relief aces, have had tentative success with Almonte and Miller, etc.