... but it is passably interesting.
Everyone knows (or thinks they know) how popular RTB1 was. Lots of people who won't remotely benefit from it, see it as an (accepted) token of True Blu-ism, an appropriately deferential and umistakable piety towards Mrs T and the hallowed Property-Owning Democracy. It fits with all known marketing wisdom, as practised by Hollywood, West End Theatreland, chocolate manufacturers, automobile brands etc etc: stick with what you know they like ("pre-sold", in the jargon) and serve it up again. "Brand extension" - there you go, that's another one.
Oh, and it could represent an actual, realistically-available, once-in-a-lifetime, 'life-changing' windfall for several hundreds of thousands, who may remember (or others in the family certainly will) how Uncle Bert really did make out like a gangster with RTB1 twenty years ago. And no-one but the Tories will offer it, so ...
Did I mention it's actually, and everyone knows it, real?
So it looks like Good Politics. "It's not funded" is a pretty lame response in the circumstances.
I'm guessing Miliballs and Clegg (a) kinda saw this one coming, and (b) rather hoped it wouldn't. Forewarned isn't always quite forearmed: knowing that when someone kicks you in the shins it hurts, doesn't stop it hurting when they do actually kick you.