Banks have been doing concierge for ages, if you're at a "expensive enough" level (and it's not as expensive as one first might assume, my bank offers a full concierge service for 10 000€ / year that's basically "it's 2 am and you want something specific and you're wherever, call this number and we'll find it for you").
I don't think tech companies can compete with that; if you want a concierge on retainer you want a guy you can talk to and explain your weird request. Nobody is paying 10+k a month to get a "barely close enough" answer. I also don't believe that's what they aim.
Instead they intend to go for the "fake concierge, but close enough": tie-ins into all their sub products, in an unified subscription and interface, at a small fraction of the cost. Oh you want an hotel ? We have that. Renting a car ? Buying a musical instrument ? Make a reservation at a restaurant ? Done. Oh, you want that actually unique request that does not get enough volume by month to be a business on its own ? No, we don't do that, but here is the google search results for it.
In other words, I believe Google One aims to play in the same court as Amazon Prime.