Hundreds of thousands of people for the first generation. Considerably less so for the second generation where the advantages were greatly narrowed vs the Silverado; since the GMT900 was designed from the start with passenger car usage in mind rather than hastily converted after the fact.
The person who wanted the running gear and much better driving manners of a Tahoe but at least most of the load ability of a Silverado.
An Avalanche had a (locking, covered) 6.5 foot bed that you could occasionally put 8 foot things in so long as they would fit between the wheel wells of a normal truck and through the midgate.
The Silverado 1500 Extended Cab had a wider 8 foot bed with horrible interior utilization while riding worse and being 10 inches longer.
The Silverado 1500HD Crew Cab had a wider 6.5 foot bed that you could not put 8 foot things in at all, while riding much worse and being 10 inches longer.
The Silverado 2500HD Crew Cab had a wider 8 foot bed while riding much
much worse and being
over 2 feet longer.
And that is why Chevrolet rushed a version with no cladding to the market halfway through the second model year.
No, the XUV (an overweight, underpowered, underdeveloped and overly complicated answer to a question that no one asked after the Avalanche had already been selling very well for several years) was the pointless one of the two, which is probably why it flopped and was withdrawn after a year on the market.
The title of the thread is not "Turbo doesn't understand market conditions of the time periods he calls out cars as being pointless in."