For typical desktop workloads memory bandwidth is not that important. They likely will release Xeon-W counterparts later with similar frequencies but higher memory channels and PCI-E lanes for those who need it.
The i7-5820K is from the "high end desktop" line of chips, derived from Xeon workstation chips. The modern equivalent is chips like the i9-10900X (note X not K), which does have quad channel DDR4-2933 and 48 PCIe lanes. Clock speeds are a bit lower though.
Perhaps, I need to take that as an axiom, right? i7 5820K was non-typical for that matter then.
And yes, Xeon-W with 5.3GHz frequency? Tell me more :)