If we really think the CBA and the aprons make keeping talent so difficult, then you have to question the Spurs strategy of supposedly working on "building a dynasty"
The better strategy, in that case, would be to build a team around Wemby to go on a short 1-2 year "burst", then break it apart right when it gets expensive, and then build it up again for another "burst"
If we truly believe the aprons are that restrictive, then it is counter-intuitive to try to build this long-term monster with 3-5 guys on the same timeline, since we won't be able to maintain them. With Castle and Harper on board, we should be looking to avoid extending Sochan for anything more than a sub-MLE level deal, we should be looking to move off Devin, only be willing to extend Fox to a 2+1, etc.