Is Airbnb simply reinventing traditional functional management? UX Lead, Marketing Lead, etc?

The way other companies slice it is that PMs are assigned a segment - for example, in an edtech company, had a manager for primary school products, another for secondary and so on. Supporting them are domain experts - UX lead with their team; a Marketing lead with their team, and so on.

The key difference is that the UX lead is deeply skilled in that area.

In smaller companies, a product manager is responsible for customer discovery. Without the requisite skills to do the job, they write biased surveys and ask leading questions in interviews. In one out of ten times, they luck out and build something that happens to coincide with what customers need enough to want to buy, but that is a 90+% failure rate. If your company has one hit product and is struggling to make a second hit product, this might be your problem.

Having segment managers supported by functional teams is a much surer recipe for success: it keeps the focus on users, rather than products, because the idea is that you want your customers to stick around long after the product is obsolete.