Just responding to these two points:
1. So you would have a Maria Conlon or Kiah Stokes transfer rather than keep them in the system, learning and growing as players until they were ready to take on the bigger minutes and contribute meaningfully to team success? Not everyone is ready to contribute in games when they arrive in college (especially at a strong program like Uconn.) Some may never, some may occasionally, and you never know whether it will work or not. And you need skilled bodies in practice.
2. Players are all unique and part of building a really good team is building chemistry within the players that play major minutes including those not starting. Especially at Uconn where offense and defense are very intricate systems, you can really mess up the development of a team by playing too many combinations of players because they don't build that chemistry - Syracuse and before them KY play systems that are close to 'organized chaos' at both ends of the floor - they have less talented players and less complex systems so running lots of players in and out keep the energy of their 'chaos' high and are not really reducing the talent mix on the floor. And they can have significant success until they run into a ND or Uconn that have precise highly skilled and highly talented rosters that can deconstruct the chaos, and punish all the obvious weaknesses it exposes. With a DePaul or a Villanova the system is much more organized and the substitutions are almost mix and match players with almost identical skills and talent levels - they all shoot the three well, they all pass well, and they are all almost the same height so it is easier to maintain consistency.
At Uconn, substituting a Kiah Stokes for a Dolson completely change the whole offensive flow and it looked really bad. Once Dolson graduated the system changed significantly and they practice specifically to incorporate her skills into the offense and defense and she was able to contribute much more and played many more meaningful minutes. Last year with Gabby, her skills were completely different from KML and enough different from Kiah, that she struggled within the concept of first team rotation and picked up most of her minutes in blow outs and rarely saw minutes in competitive games or the NCAA tournament. The team could deal with two sets with and without Kiah but trying to add a third variation to cater to Gabby just wasn't worth subtracting from the work being put into the first two. This year with Kiah and KML gone, you had in effect two sets with and without Gabby/Napheesa. Next year with the graduation of the big three we will probably see two sets with and without Butler. (And yes - it was clearly evident that with Natalie missing the first two months, the team moved on without her and never re-integrated her skill set once she returned. One reason she looked so 'out of place' when she did get minutes.)