Wasted x years not being in prison?

He basically imprisoned himself for all of those years. And what's worse - those years won't be subtracted from whatever sentence he's going to get. I don't understand what his long-term plan was.

If I had to choose between being stuck in an embassy and being in a US prison, I wouldn't think about it twice.

Yeah, but without a proper exit plan - you're only delaying the inevitable. He has spent 7 years in the embassy and 4 years in an UK prison - and his trial hasn't even started yet. 11 years and counting - many murderers don't get that much.

Well yeah superpowers can do whatever they want.

To be fair to the US they don't push you out of a window. You get your day in court (although it may take several decades- see Guantanamo bay).