this was discussed previously on the rnbo topic
the main issue is, not for current release of RNBO, but no solid statement on what a future license , may or may not look like.
so the issue isn’t really using RNBO 1.0… thats pretty clear.
but if you put alot of working into a ‘product’ , sure you can ship it now.
but you are likely to want to upgrade to 2.0 in the future … and that may not be possible if the licensing terms are incompatible with your needs. (*)
so a large project, esp. if its commercial, would be a risky undertaking…
and frankly, the risk/benefit ratio for most developers would not be worth it.
its also not that appealing to open source projects for similar (and other) reasons.
which goes back to my previous post… whats its useful for? (**)
as I said…
developers might use it for prototyping, or for small/non-commercial projects.
non-developers, really its, quick n’ dirty solution for one-off creative projects.
like or not, I think thats C74s market…
I think they see this as something for individuals to create ‘one-off’ custom projects, rather than as a ‘development platform’ - some will feel that vision is pretty ‘limited’ 
personally, I feel RNBO will have limited appeal, until it gets rolled into the standard max license.
even then, Im not sure, it will ‘take off’ until Ableton Live has native RNBO support under ‘Max 4 Live’.
… I see that could change things, as I think M4L developers are a natural market for RNBO.
(though lack of live integration may be a big issue)
frankly, I think some social media , like CDM, got a bit carried away with RNBO… heralding it as the day ‘musicians could write VSTs’.
that was never the case, nor do I think it was C74s intention - C74s marketing was much more modest in its ambitions.
anyway… for now, just another tool for the toolbox… nothing revolutionary 
(*) in fairness, this could happen with any 3rd party SDK… any developer could stop developing its current version , and release a new SDK which has a new license. JUCE did something similar to this.
(**) also Id point out, rnbo 1.0, has many quirks and limitations…
one of the most misunderstood parts of rnbo is, its actually 2 main parts
- the code generator
- the template
together they form the ‘functionality’
the issue is, there are many limitations in the current templates - and only developers will be able to realistically change these.
however, these templates are also limited by the code-generator, which we have no control over.
if you look at the C74 forum under RNBO, you can see this is not well understood by many, and even less understood are the implications/limitations.
also, honestly, my experience so far, is C74s support of RNBO has been pretty poor… I think they have underestimated the amount of ‘development support’ thats needed, and some glaring issues have not been addressed, nor many even commented on.