Look, if people don't want to train players, that's because they don't know a lot about the game. So, they are in a low division. If they are in a low division, 750k would be a good help. And, in normal conditions, a player well trained,after 2 seasons would give at least 1.5kk.
In the case that we are not talking of a low divison team, 20k salary won't be such a diference, so the team can train 2 players for 1 more season, maybe 2. And that would surely give some profit.
And, if a player trains 2 positions, their players will get lower salaries but, instead of being 2 high salary players, there would be 5 medium salary players, so the difference would not be high.
As you said, this is a long term game, so losing 4 years to build a good team is not wasted time