This sort of portability is usually handled by the DB routing layer in cloud native ("webscale") database deployments. eg in Cassandra.
of course there are a lot of systems where one MySQL DB instance is needed and sufficient for the forseeable future. so that's a very static resource allocation one VM on a hypervisor with local disk, (and with backups every day), makes a lot of smaller sites very happy, and if they get the local provisioned performance instead of the EBS variant they will be happier for longer.
of course, EBS is a lot more fault tolerant.
EBS is a compromise, its allows your data to run anywhere in a region, on any machine. That means lots of hops and lots of interconnects.
the latest SAS stuff runs at 12 gigs(most likely 4 lanes per cable, and dual linked too.), _but_ thats dedicated for local traffic. The performance difference between having a SAS disk inside a box, or in the next rack is negligible. A decent SAN that exports over a 56gig connect (inifiniband et al) will be >> than a local pcie in terms of iops and sustained bandwith (at the expense of latency.)
Crucially, in somewhere that runs it's own datacenter, the storage is modelled for a specific workload. In VFX land we had 32 60 disk file servers, each capable of saturating two 10 gig ethernet links. But it'd be appalling for mixed VM hosting.
EBS is a hedged bet, it had a _boatload_ of caching to make any sort of performance. It had a huge amount of QoS to stop selfish loads stealing all the IOPs.
To get the best performance from EBS you have to have large volumes (5Tb+) and large latest generation instances (c5, r5, m5) 4 or 8/9 xlarge ec2 instances. This costs money to run.