> You seem to be focusing strictly on performance,
Just like the vast majority of buyers do. SPARC was abandoned by customers due to poor performance.
> but there were other factors: e.g., remote management is still a bit of a mess with x86
That's a property of the systems integrator, not the ISA. Dell's iDRAC works quite well.
> Dell's iDRAC works quite well.
I currently admin several racks of Dells (and Lenovo, and SuperMicro, and previously HP). Just make sure you buy the license for KVM in case you ever need to go into single-user/rescue mode (otherwise better not mind having to drive to the DC and hooking up a crash cart).
Ask @bcantrill (the author of this article/story) about how well integrators integrate (as a hint to the answer, he co-founded Oxide Computers because he ran a cloud service with Dells/HPs/etc).
You can ignore KVM license if you have good netboot infrastructure and only install OS in UEFI mode - SOL works fine.
The big issue is usually "remote media" support, thus my recommendation for setting up netbooting infrastructure
Integrators integrate very well at the level that they're operating, i.e. the single server. Rack-level integrated systems are a whole different thing, very specialised and unrelated to the old thing.