@thousandfold - I should note that I do not have Lumina, just Symphob 1&2. Nothing against Lumina - It just didn't interest me at the time when it came out because of what I already had (a ton of stuff). But, it does have a much better list of solo instruments, etc and it seems to be a more recent approach to the orchestral sample game (re my comment about I and II having been out of a long time).
If you're just starting out, know that you'll be adding tools as you go. There are lots of decent tools out there to get you started, and you'll come to use them less as you add more things to you arsenal. But, don't let that deter you from diving in. The Symphobias do sound good and are incredibly quick and easy to work with (which is a great plus). Just don't expect them to do everything under the sun - nothing can. I have probably gotten more use out of the symphobias than Albion One (narrowly), but you can't go wrong with either to start out. That is a tough call, as they're both good and useful.
My earlier comments were more addressing your specific question of why people don't use them for 80% of a piece in final product. I think that is just the ensemble approach. I have certainly done entire cues/pieces with both/either of them independently. It's just that as I've added more libraries I've found betters ways of doing things to my liking. You work with what you have and you want to learn what it does and doesn't do well.
EW composer cloud is just a different animal, as that is more of the usual/non-ensemble type of orchestral library (individual instruments or groups). Personally, I hate their software. Others are fine with it. If I were just starting out I would probably be willing to overlook it at those prices. I did use a lot of EW products on projects when I was more willing to put up with their software. There are just better things these days in my book.
Regarding the wind patches for ensemble libraries - that's a personal thing for me, but winds are the most individual of instruments. They're pretty much all different. It isn't like the strings where they just have variations of range and size. The winds all have different dynamic contours, different sound production techniques, different overtones - doubling them all the time sounds like an organ. That said, Lumina looks to have a nice list of better options for winds and solo instruments.
In short - ensemble orchestral libraries aren't the only approach, but Symphobia and Albion One are well worth getting if you want to go that route (and it is a good place to get started, for sure), and also for getting started in general.