And with the rate at which Pluralsight is acquiring other companies, it'd be a lot more expensive than 1.5B

Maybe, but Pluralsight looks more like it's aiming for an IPO to me. They've made quite a few acquisitions but then not really integrated them much into the core product - mostly adding big lumps of subscribers and revenue to their numbers which looks better for an IPO than an acquisition.

I don't believe that's a cultural mesh that would work.