Yes, of course, he has no power to demand a high cut or even an even cut because Spence is still a better PPV attraction than him and has more achievements in terms of the belts they are currently holding. Crawford should accept the terms of Spence as long as it's reasonable to make this fight happen.
I'm not sure if Crawford doesn't have any power to demand more money, actually I'd think Spence is asking big money because he is the one who doesn't want to fight Crawford, instead he's asking big share, so he make Crawford to think fight with him isn't profitable.
Crawford have better statistic on pound for pound rank [1] and greater point too than Spence [2]
[1]
https://en.wikipedia.org/wiki/Boxing_pound_for_pound_rankings[2]
https://en.wikipedia.org/wiki/Welterweight