I don't think it is the money aspect to be honest. One guy in my league had the 9 star youth player and 2 8 star from boost lab, he also received another 9 star striker 27 yo out of nothing a few days ago. (I think from boost lab again)
He is 148% quality. Here on server top we have many strong teams, some investors, some green farmers. Ok this boost lab guy, he did reach the semi finals of the CL where I beat him 3-1 and 7-1 and in our league he sits only 11th place. Ahead of him some free to play players as well.
I mean I lost in cup vs a guy who despite having a good team, he didn't even have the Mourinho support in these games. He bought it later though.

I think a lot comes down to tactics and formations in todays game.
But I am 100% convinced, that Nordeus is giving some teams bonuses in some games or makes them harder for the other player. I noticed very often that my team is hitting a bad phase for a few days while other rivals win every game comfortable. It is only to be thrown out of cup or CL in like the span of 3 days... And later in the season or next season the others have the same surprising slump.
Of course this game will make sure, that out of the active players, many of them keep on playing the game and want to buy sponsor, invest money and such. Thus we hit a slump, that another customer doesn't quit.