I don't feel this is the be all, and end all of English rugby.. But I do feel it will be for a Lancaster.
As far as the selection process has gone, I always thought Cipriani would make it. I pinpointed him as the "x-factor" in England's ranks. You know, how Australia has Foley and Quade, NZ has Carter and Barrett, etc. I thought it was going to be Farrell and Cipriani. I won't lie, I think the rest of the rugby world had a sigh of relief after hearing about Tuilagi too... He's dangerous, and I'm nervous when he plays.
I mean, I know that the English fans would have demanded their team make the semis, via finishing top of their pool, and isn't that still possible? But if they finish second, it's South Africa. We don't know what is going to happen in the England vs Australia game, literally anything could. But the unfortunate part about it is that Australia had been very mediocre over the last two years, until very recently. And would have been brushed aside by the likes of England, Wales, and Ireland. Everything is still on the line, but Australia are most certainly different.
In regards to England's future with rugby, it is extremely bright. They are coming. You don't win back-to-back JWC, and be runners-up a few times to not produce talent. Look at New Zealand and the kids that come out of those teams when we were winning. It's just about how your country gets them into the right positions and exposure, in order to be successful. This is what I feel New Zealand is better at doing. But yeah, future is very bright for England, if things are done properly.