Why don't countries enter proper bands/artists for eurovision?!

Why don't countries enter proper bands/artists for eurovision?

i.e iron maiden.

ok, look at the winners last year, they at least 'broke the mould' with their rock style rather than dance pop etc.

I'm interested to find out why signed bands don't usually enter, it is a rule?

However, the pop band scooch (is that right?) did have a label a few years ago and then broke up and reformed for Eurovision.

The thing that bugs me is think about how many times Ireland have won the Eurovision Song contest. LOADS! and understandably it was getting too expensive for them to hold it each year and have now let their standard slide a little so they don't win. (sorry recent Irish entry)

aside from the fact that it is a little racist at the moment, and western european countries get ignored by eastern european countries when it comes to voting, don't you think the United Kingdom (i.e. England, Scotland, Wales and Northern Ireland) would have more of a chance of winning if we went for a traditional style song, perhaps a celtic theme focusing on the other countries that make up the UK, not just England(!!!) to a style that Ireland were doing on their winning streak?

Anyway, it's worth watching just to listen to good old Terry Wogan!