I believe on the ARK he wouldn't have been allowed to grow it out. Maria probably would've fought for it if he'd shown want in letting it grow out. But he found short/no hair to be pretty practical for himself.
But I think if it wasn't Rouge, it'd be Sonic or someone else who'd convince him to let it grow out a little.
Despite minor complaints I think he really does enjoy the process of haircare and all, yk? It's often a long intimate process to trust someone with your own head and hair like that.
Plus he wouldn't wanna look like blue faker 1 and white faker 2 would he.