I imagine most everyone shares understanding of the long term effects of a barren farm system but here's a couple thoughts:
It takes 3 -5 years to graduate a competent , home grown from your system to the MLB level. The system keeps refilling every year from the bottom up. You are never too far away from reloading (2 seasons?)
When you win consistently, you draft later lowering your chances of getting a stud. On the other hand, look up Patriots, New England for an alternate theory.
Each year 30 teams show up ready to win it all. About 15 of these have no chance going in, Wrong place in the cycle, wrong players, manager, organization , no money nor appeal to FA's, etc.= No chance
Of the other 15 , 5 would love to just make the WC game , 5 more expect to be good and 5 think they can win it all. 10 make the playoffs and a 2 days later , it is down to 8 remaining . Maybe 1 of the 8 gets hot and beats a better team. Now you have 3 strong teams plus a lucky dog. One each representing their league move on to the WS. Only one team of the 10 that made the playoffs wins its last game. Everyone else lost. The prize is to be that ONE, not whether your farm system won 4 of 5 lower level league championships. With a team like the Red Sox in 2018, you have got to go for it all at whatever expense, budgetary or future talent. People would have had to experience the futility of the 50's, 60's, 70's, 80's, 90's to fully appreciate why it's hard to care about the players at Pawtucket, Portland or anywhere else.