It's funny and sad how true this is.
I think everyone would be able to predict what would happen if Havertz stayed another year.
Bayern: Hey Leverkusen, we give you 10 Mio for Havertz
Leverkusen: Oh, that is really not that much, he only has 1 year contract left, but 10 Mio? Well, we sell Havertz to another club then.
Havertz: I will only play in Bayern, because I already got a contr..... errrrmmmm... a continuous wish to play there.
Havertz to Bayern without any fee in 2022.
Hoeness: We want good opponents in Germany, they should really work harder, like we do.
Great narrative you've got there...Bayern signings of Bundesliga players over the last five seasons...
Pavard: Stuttgart was already relegated and needed the money, he was leaving for a club abroad or Bayern. The 35m € fee was very good money for what is basically a player who's above average at RB and CB but not great in either position
Kimmich: Stuttgart mismanaged one of their young talents, didn't even let him play for the second team at one point. Their management at the time was very happy with the money they got for a player they didn't have in their plans. Bad management on Stuttgart's side but just good scouting and business by Bayern.
Hummels: Dortmund had to rebuild their team because the 2013 core was disintegrating and the time-line was not aligning for Hummels for whom we paid fair market value. He also was a homegrown player who we lost due to mismanaging his contract several years earlier but he still had strong personal ties to the city.
Niklas Süle: He was a nice central defender for Hoffenheim and certainly a known talent, but the 20m € fee was representative of the fact that there were doubts about his ability to actually make it at the highest level. In today's market a steal but in 2017 hardly anybody thought the fee was anything but appropriate.
Leon Goretzka: He was linked to Bayern as an 18 year old from Bochum and had an offer. He decided to join Schalke04 instead. On a historically and awfully low release clase in the low seven-figures if I recall correctly. It was the steal of the century for Schalke. Schalke then passed on several opportunities to sell Goretzka until they backed themselves into a corner with their mismanagement of his contractual situation.
Serge Gnabry: Doesn't really count. Without our guarantee to buy him the year after Bremen doesn't get him from Arsenal in the first place.
So in total one player who joined Bayern on a free in a situation close to what you're describing and in that situation Schalke got the player on a shady release clause in the first place and then went on to badly mismanage his contractual situation. Hardly a conspiracy by Bayern to avoid paying a fee. Schalke was just incompetent.