I wonder if the difference lies here: whilst there's 'commercial classical' and 'uncommercial pop', there are almost no avenues for the latter to gain wider exposure, which is not the case for 'uncommercial classical', because there exist institutions who will promote and organise performances of the latter with some (varying) degree of independence of its commercial potential (because the money required to put it on is to some extent guaranteed via subsidy, rather than depending on successful revenue generated through sales, advertising revenue, private sponsorship, etc.)?
However, shows like that of the late John Peel were a subsidised avenue for less 'commercial' popular music to gain some exposure. Shouldn't forget that Radio 1 is just as non-commercial a radio station as Radio 3 (I think).
This is a point that's very close to my own heart, as much of the 'pop' music I like is decidedly uncommercial. Bands I like won't even be looked at by Radio 1 and have little chance with any of the other 'pop' stations.
I believe it is part of Radio 3's remit to commission a certain amount of new work each year. Where is the equivalent requirement for Radio 1, Radio 2, and even BBC television to do the same for pop music? It's a system of market-place subsidy that actually favours classical music over 'minority interest' pop music, which surely must be completely against the spirit of the BBC charter.
A while ago, fans of a particular band I follow were attempting a 'grass roots' campaign to get the band an appearance on Jools Holland's television programme. The campaign was dropped when investigation revealed how much money it costs to get on the programme. Television (and, we assume, radio) is only for bands with a big marketing budget. Which is completely wrong, in my opinion.
The BBC actually favours new classical composers over new popular artists, by giving a outlet (not to mention subsidies) to the former with no equivalent outlet to the latter.
John Peel was an exception: one man who managed to gain an influential voice, rather than a reflection of Radio 1 policy. In the absence of policy, it was his personal taste that dictated which bands were 'worthy'. He was a law unto himself, and incredibly capricious -- your first album might be the best thing to happen to pop, your second might show you as complete 'sell outs', in his exalted (and unchallenged) opinion and you would never be heard on his show again. Let's face it, Peel was a musical snob of the highest order.