If he actually had $1 trillion in cash, maybe. But he doesn't, the vast majority of his wealth is paper wealth. To spend that money he has to borrow, sell assets, or tap into whatever his cash reserve is.

It's not equivalent because $400M is an insane amount of disproportionate power and influence. In this specific instance it broke down likely due to the cultural zeitgeist and general dissatisfaction with costs and Trump but in a less tumultuous political environment, that amount of spending should always be corralled and limited.