at what point is a good cross-country hardtail going to be superior?
Almost all the time unless on tarmac or super smooth gravel with average speeds over 25kph. Unless it's a insta-wagon steel gravel bike with a high and wide bars, then a 29er XC race bike will be faster everywhere.
Gravel bikes are a good compromise "one-bike quiver" but if you already have a road bike, especially a modern one with 28mm tyres, an XC bike is definitely the way forward as a 2nd bike.
I've really had the urge to build myself a rigid xc bike as of late. However, I'd only ride the same trails as I would on my cx/grave bike so I don't see the point. Specially as there are some decent rode sections between...
Almost all the time unless on tarmac or super smooth gravel with average speeds over 25kph. Unless it's a insta-wagon steel gravel bike with a high and wide bars, then a 29er XC race bike will be faster everywhere.
Gravel bikes are a good compromise "one-bike quiver" but if you already have a road bike, especially a modern one with 28mm tyres, an XC bike is definitely the way forward as a 2nd bike.