To further the point with @Riverbrian, even many of the most internally developed teams (i.e. Rays) consistently bring in veterans to fill out their roster. In reviewing who has or had been their current 26-man roster as posted on Baseball-Reference, I count 20 of 33 players that have played games in 2025 for the Rays that have played games for another organization prior to being signed by the Rays. The list is: Jansen, Morel, Diaz, Caballero, Rortvedt, DeLuca, Montes, Palacios, Littel, Pepiot, Rasmussen, Fairbanks, Bigge, Clevinger, Uceta, Englert, Rodriguez, Orze, Boyle, and Sulser. If you want to argue that some of these players only played a few games for another team and then signed (or was traded) to the Rays, fine. But the point is that over half of their roster has played games for another team at some point in their career and this is supposed to be the team that specializes in developing their own players. The idea of being able to develop your own 40-man roster is insane.
Let's look at the current situation at 1B. The Twins sign Ty France, which to be honest, I was not a fan of as even I had wanted them to use in-house options and save the money to spend elsewhere. As it has turned out, France has been the best option at 1B that we have had this year. Kirilloff is now retired, Julien has games at 2B and seems to not have decent defense at 1B, Castro is banged up and better served elsewhere, and in the minors, you have Severino who seems to have stalled or Sabato who has been a disaster of a draft pick ever since he was drafted. As the season has progressed, who would you suggest internally should be playing first other than Ty France
Every team has developmental strengths and weaknesses. Bringing in Falvey and Levine, we were supposed to shift to pitching oriented development as quality pitching (other than catchers) is the hardest position to develop in the majors. That focus will leave holes in developing your position players, be it hitting or fielding (as we can clearly see in the current style of play).
If you want to make the suggestion that small and mid-market teams need to develop their own star players, I can agree with you on that point. I would guess that small and mid-market teams' fans are more in tune with their minor league players as they need to lean on their minors much more than large-market teams.