Sure you can, companies patent ideas constantly and then extort other companies with money because invalidating a crappy patent is extremely expensive from legal perspective.

Don't mix theory and reality.

Tell that to everyone sued with the Magnavox patent.

my partner has a patent for the idea of adding texture to a glass touchscreen. she got this patent while throwing ideas at the wall in a meeting paypal has to just come up with patent ideas

You certainly can. What you can't do is patent and be 100% sure that it won't ever get invalidated in a challenge. But that never happens, because the incentive landscape makes it more attractive to licence: a company licencing instead of challenging passes the buck to its competitors, and even more importantly to potential future competitors. Patent troll companies are effectively offering moat-as-a-service and those moats perform just fine even if they are just imaginary moats.