The orchestral libraries you seem to keep referring back to were specifically designed as ensemble libraries, for the most part. Albion One has some nice stuff like violins recorded in octaves, because being recorded that way sounds better and more realistic, generally, than layering a sampled violin 1 with sampled violin 2. Same goes for woodwind patches were the winds are recorded together at the same time versus individual patches layered in a DAW. (Albion I/One has a great celli and basses in octaves patch, by the way).
The problem is, good orchestration is seldom just layering things all the way through. So, aside from the extremely useful process of using these libraries for sketching (the advantage being having the range of the whole antiphonal section at your hands, instead of just the violins), these libraries can be very useful for specific choices. (they can also be very useful for getting an approximate sound very quickly if you need to send a mockup to someone for a general idea fast - which happens all the time). But, no - I would not generally use these libraries straight through an entire cue/piece if it is reasonably complex - maybe if it is just a bunch of pads. Limiting yourself to doubled sounds all the time is just bad orchestration and it sounds like it. Especially with the winds - I want to choose how my voicings are voiced - I don't want a Kontakt patch choosing that for me. But, if I want to send a mockup to someone and don't need all the specific detail in there, sure - they can be great because they're fast.
There are certainly examples of people going and making good sounding pieces with these libraries, or even the CineSamples CineOrch lite library. But, they clearly can't do everything. If you're going to do that you have to write to the strengths of the libraries and avoid their limitations - this is true of any library. And that is why people use a whole bunch of things. Good orchestral music has a lot of detail is incredibly hard to mimic well. If you want the be free to write what you want, then the more tools at your disposal, the merrier you will be in that regard.
And then there is the consideration of when these libraries came out. I used to use Symphobia a fair amount when it first came out. That was ages ago and there are things out now that sound better to me with greater flexibility. This technology will always be changing, so you might get use out of something now, and then something better comes along.
I've been working with this stuff for over 20 years, and man has the technology changed. I just accept that it is a major investment, and coming from a background of live music, I have certain expectations of how things should sound. Because of that quest, I've bought a lot of libraries that I didn't end up using very much.
What I've ended up using a lot of for orchestral libraries - LASS, CineWinds, and CineBrass. LASS is a bear to learn and get setup right, but then it can do things other libraries can't come close to because of the individual control of timing and tuning within a given section. CineWinds and CineBrass are just very fast to work with. If I were going to just buy 3 orchestral libraries, they would be it. They are what I use the most of. Next string library in use is Spitfire Chamber Strings and then their brass library - but, I honestly haven't done a lot of brass stuff since the revamp, so maybe Spitfire would take it now for me. Not sure.
That's my experience, anyway.