What I have been saying about ARM servers for years. Once a company makes the leap, they are now in a situation where they might consider a different ARM hardware vendor. Going back to a x86 platform is a huge hurdle. I know some people write off the market penetration of ARM in datacetners and servers. I think ARM is over 25% market share in datacenter now. They are shrinking the customer base potential for the x86 companies.This is why getting the fabs up and running for 3'rd parties is so critical for Intel; there is a very plausible reality where Intel's fabs are worth substantially more than the CPU and design side of things.
Intel and AMD can happily trade x86 clients back and forth every couple of generations, but every client lost to ARM is a client lost forever.
If a client is willing to make the transition over and rebuild their platform accordingly, they had a hell of a good reason to do so, and winning them back will equally need one hell of a good reason, and neither AMD nor Intel has managed to provide one yet.