As of 2024, WWE is worth $8.37 Billion.
TKO, while being a parent company of WWE, does not have operational control of the company, that is contingent on the Board of Directors. Just because a parent company has more money, doesn't mean they're gonna splurge a shit ton of money into the child company just to sign one fuckin' guy lmfao.
Tony Khan can and has historically competed with WWE for contracts, which is why he's gotten a majority of recent indy talent compared to WWE, who generally goes for homegrown talent.