Why IA does not invest ?

Hi everyone,

I have a little problem: I've noticed for a few years that even when I increase the finances of an AI club by a lot, its squad doesn't really improve and I can't make a league stronger.
 

I wanted to make the Austrian league much stronger, and even though I gave RB Salzburg a budget of 80 million, they hardly buy anyone, only one or two average players for 5 million for example. Is this only due to the reputation of the league and the club?

Thanks a lot for your help ! 

Because it's more complicated. The club will not suddenly buy 11 Cristiano Ronaldos because they will not be able to handle their financial demandings next season. Spending depends on popularity, fans attendance and potential of their increase (which will not grow if stadium is already full every match), trophies or whether the flow of money will be constant (sugar daddy), and so on.