The BBC is operating in a commercial market and has to pay rates which compete with what they could earn elsewhere. The commercial operators are willing to pay very high rates to attract top talent because even at these rates they will attract more income than they cost to hire. This is no different from top sports stars or top musicians. At one level they seem ridiculously overpaid, but looked at another way all they are doing is demanding a fair proportion of the vast income they generate for their employer.

If we want a public-service broadcaster it has to be able to fish in the same pond for talent as the commercial ones. That means paying what the market demands. Whilst the BBC is funded largely by public money via the licence fee, this does come only from that proportion of the population which owns a TV so while the licence fee is a tax of sorts it is at least levied on the people who are most likely to benefit from it. And as Steve says, it is incredible value for money.