Basically Windows 10 was released 6 months too early. I don't really understand why they were so desperate to release in July? Surely it would have made more sense to push back to October (Threshold 2 release window)
You're right in saying that it would have been a better release if they'd waited for Threshold 2, but that's different from saying it would have been better to release it then.
July 29 hit the back-to-school sales market, and Microsoft must have calculated that OEMs would sell more Windows 10 PCs than they would have sold Windows 8.1 PCs.
So Windows 10 didn't have to be technically perfect, it just had to be more marketable than Windows 8.1, which it is.
The move to continuous updating helped, of course. Microsoft wouldn't have been able to release Windows 10 in its July 29 state if that had meant committing to shipping it in the same state for several years.
You're right in saying that it would have been a better release if they'd waited for Threshold 2, but that's different from saying it would have been better to release it then.
July 29 hit the back-to-school sales market, and Microsoft must have calculated that OEMs would sell more Windows 10 PCs than they would have sold Windows 8.1 PCs.
So Windows 10 didn't have to be technically perfect, it just had to be more marketable than Windows 8.1, which it is.
The move to continuous updating helped, of course. Microsoft wouldn't have been able to release Windows 10 in its July 29 state if that had meant committing to shipping it in the same state for several years.