Selling your time doesn't scale
Sure, but it continuously opens to you new opportunities to unearth something that does scale, but isn't available yet...
In any normal employment you don't get that.
a) It doesn't need to be your time exclusively
b) Time-based pricing is only one pricing model for consulting businesses.
I'd add that, funnily, I sometimes hear this from FTEs (who sell their time) or product entrepreneurs who eat ramen for five years and then have little to show other than the time they've spent on the product. Meanwhile, some consultancy owners make real bank... It's fine if your risk profile allows you to do product, but if it isn't obvious, a service business can be totally legit.