It might come as no surprise but there are a lot of humans in games. Modelling a human isn’t really rocket science anymore and the actual high poly sculpt phase makes up a relatively small section of the overall model production process. It’s certainly not the most challenging nor the longest stage of the process in general (there are exceptions obviously) so there is really no big reason to replace it with photogrametry unless you are looking for the exact likeness of a certain person.