I mean, explicitly, beyond "companies are upset about hypothetical problems". Has there ever actually been a problem? Say, has anyone ever been sued for patent infringement upon using MIT licensed software?

Fun fact: there is also no express patent license in GPLv2. There have been lawsuits on that. I know because I was the lawyer who filed one of them. So...yeah, this problem is not hypothetical.

You should hire lawyers to improve your contracts before the ambiguity in your old ones cause lawsuits.

That said, “Blue Oak” is a terrible name and will cause even more hassle than “Apache” when dealing with non-technical folks.

Explaining to the CFO that we license <component> to customers under “Apache” terms to avoid internal legal issues for our customers is... hard.

I was always under the impression that BSD or MIT + patents was Apache2?

use Apache-2.0 then. It's longer in text but people are already using it and know what the terms mean. The point of the whole exercise is to use a small set of well-known licenses and keep things out of the hands of lawyers (which is admittedly the opposite of what Blue Oak wants)