wp10.5 will fix it! (I like to stay ahead of the pack) ;-)
Anyway, only after WP offers something a LOT of people REALLY want, something that is easily marketable and demonstrable on TV, and which iOS and Android devices lack, only then will things change. So far I'm not aware of any such w10 related feature. The most important differences we know of are once again concerned with unification and under the hood changes. The good news is that this time, MS really will have arrived at the destination of their unification journey. That will open a lot of doors and possibilities, but as of now I think that is merely an enabler. By itself, it's just nowhere close to being a winning move. I'm actually more interested in what comes after wp10...
If wp10 turns things around, it will be done by something we haven't yet heard of.
The thing is, it's not enough for W10 to be successful on traditional computers. It has to be successful in creating demand for Windows Store apps, which might not happen even with it being wildly successful. If people just continue to use the same software they always have, nothing changes... My problem with that is that I don't perceive Windows Store apps to be the kind of thing desktop/laptop owners have long been waiting for.