It’s due to the technical requirements of a DH bike – the rider relies on technology too much, compared to XC racing (which although has a high element of technology – leg power is still the main requirement!! )
Not entirely true. It’s not like F1 – the technology is available to all, and the fastest rider that season is generally the faster rider that season, you don’t hear about 2nd place complaining that he just wasn’t on the right bike that year.
XC = lung/leg power
DH = technical ability
Secondly, it’s not very spectator friendly – the XC races are laps, so you can see the riders pass you several times.
I honestly don’t know how to reply to this. Are you saying that XC skiing is a better specator sport than DH skiing? Have you ever actually watched a XC mtb race? I used to race XC, but it’s dull as dishwater to watch (I was at Dalby last year for the WC, slept on the grass for most of the day).
It’s easy to see all of the course when watching a DH race weekend.
EDIT: to be perfectly honest, despite my love for all things bikish, i get quite bored watching any discipline.