Once again, and I'll repeat for the final time, you're missing the point of the argument; you could have said they'd come out with a kill ratio of 1,000,000 to 1 and it wouldn't have mattered. It's a fictional scenario based on specifications that are currently theoretical and nothing more...it may well be the case that all of those capabilities are realised, equally it may be the case that none are realised, it'll probably be somewhere in the middle, but at the moment, past experience suggests there are very big hurdles ahead.
The reason people are so pessimistic about it, is that we have seen much less complicated aircraft run into significant and costly problems, which in some cases have not and never will be resolved. People are rightly questioning the value for money, particularly as we're sacrificing so much for such a small number of aircraft that will be no-where near the end of their test programme by the time we have them in service...