The problem is that for these companies, they're in danger of being burdened by copyright issues, as somehow everyone forgets that designs are copyrightable in Europe, and unlike programmers most designers don't really want legal uncertainties when it comes to their designs (because it's damaging in their circles). If they're designing from scratch, they hold those design copyrights and designers can rest easy knowing that they won't get sued.
It was cheaper than licensing a couple of fonts we liked. So we asked the designer of one of these fonts to tweak their font to our brand, and license as new IP under new name. Because it wasn't entirely "from scratch" the price was reasonable, around $50k.
However, if a design team wants to make their own font and has the resources to do so I don't see why not. It's a strong branding move.