Potentially, yes. I think certain extant versions of Houdini link against 2.x, and this it's use is forced for somebody incorporating OSL into a Houdini plugin. In fact, a few such unfortunate souls are in your very building.

You know, if it were really burdensome, at some point I would say "OSL requires x.y, too bad for the rest of you."  But currently (as you can see) there are probably only 30 lines of code in the whole thing (now conveniently in just one .cpp and one .h) that are not fully compatible with everything from 2.8 through 3.3.