Your main argument is that a 100k player in division 3 is affordable.
And fine, if you have a 100k player with a bunch of very low salary players then it is affordable. But you will not see many (if any) good teams with that kind of player in div 3. It is much better to have 5 20k salary players.
I may only have 1 season of experience, but I still promoted, despite being a league where there were numerous teams that had been there for seasons and many had a much better team originally. It's not all about experience.
And it's not like ripping up a winning lottery ticket, it's more like taking a 10 million dollar payout now, rather than taking 15 million dollars total but paid 1 million a year over 15 years.
You might say that having it paid over 15 years is the better option, or you might go with the 10 million right now.
Both options have their benefits and both have their pitfalls.
If he thinks having a 100k player in div 3 is what he wants, then let him keep it. But he would be much better off, in my opinion, with 5 players with 20k salary each, and a bunch of old players with decent skills. Which he is much more likely to have if he sells his HOF player now, and buys new trainees and new old players.
But ultimately, to each their own.