Concept Bikes & Bike Innovation - for better or worse

There were aluminum frames long before his.

As I understand it, the claim related to welding oversized tubes, rather than just using aluminium, which as you allude to goes back to the first half of the 20th century. The US patent office has a long and dishonourable history of granting patents where the claims clearly don't meet either the "no prior art" or "non-obvious" tests, so much so that a cynical person might conclude that they're getting kick backs from the lawyers involved in the inevitable subsequent litigation