This isn't going to affect Intel usage in the near future.

True, it won't significantly shift the downtrend Intel is experiencing but it's one more reason why that downtrend exists. Corporations are already switching over to AMD's EPYC for their server platforms and Intel is as entrenched as ever in the Laptop side of corporate business (which runs Windows anyway)

Companies generally buy whatever is cheap and available

Not quite true, they buy what makes them the most money for the cheapest price and due to that context Intel has been on the way out for a while now.

Dell, HP, etc rarely offer AMD as an option.

While there are a lot more systems available with an Intel chip saying they rarely offer AMD is stretching it a bit. Dell has listing for 51 Intel and 12 AMD laptop options, HP ~190 Intel and ~90 AMD, there is an imbalance there but if you are a corporate customer looking for something you will find an AMD alternative there. And in the server space Intel has been/is being gradually reduced to the second choice option with AMD EPYC being chosen for the premium products.

And this is just ancillary Linux drivers, not a major make or break component.

Might be ancillary to you and me but to a corporation this is a piece of liability they now would take on when buying new Intel CPUs for servers. Not by a lot but likely by enough to upsell them to the product using AMD instead.