I'd suspect that (from Apple's perspective) any form of file sharing (other than iCloud) is now considered 'extremely niche.'

If they were focused on the needs of the kind of person who moves enough terabytes of files around to need this kind of speed, we'd see them still making either computers with slots, or first-party 25Gbps networking.

I'm not really trying to criticize them for it -- Tim Cook's bean counters clearly did the math and they're certainly free to optimize their Mac R&D spend for things that'll sell college students MacBook Neos and Airs, rather than worrying about the MKBHDs, Linus Sebastians and Jeff Geerlings of the world (this is just a list of people I've seen using extremely fast networking).