I do not ever measure bevel angle and have never honed a razor that will not shave.

I doubt that folks were measuring angles in the early 1900’s. Bad uneven grinds and warps are another thing and I think are the cause of a lot of honing issues that the bevel angle get blamed for.

I hone warped razors in 3 parts. First establish that the razor has a warp or hollow by putting it on a flat surface. Hone the concave side in 2 parts, hone the heel with a rolling X, but keep the heel on the stone until halfway. Then hone the toe starting with half the heel off the stone. Ink the bevels so you can see where you are making contact.

Then blend the heel and toe by doing a rolling x where the heel comes off the stone at the beginning of the stroke and ends at the toe at the other end of the stone.

The convex side is honed with a rolling x but rolling up. The amount of rolling up or down depends on the razor and where you are removing ink, but it is generally very little.

Ink will quickly tell you what is going on at the edge. I use ink on every razor, it is not just a learning tool. Colored ink is much easier to see.