It is negative, but you have understand how niche the music and audio market really is to put some of my comments in context. I'm all for new and cool and all the rest of it, but the end users here--composers, musicians, producers, engineers--tend to not care so much about pioneering in what you might call the HN way.
To speak to your simple example, Native Instruments could do what you suggest, but they could have done what you suggest by adopting the cool and new VST3 standard back in 2006. This would have set them up for Cubase 5, which introduced VST Expression (3.5) to provide exactly that variance within orchestral samples on a per-note basis. So this has been possible for nearly a decade and a half, and, so far as I can tell, while most composers agree it's a neat idea, by Native Instruments controlling the sampler market (and Vienna to a degree) and not supporting VST3.5, the adoption never materialized.
Also, how many keyboards support polyphonic aftertouch? This would be the MIDI message that would need to be generated in order to perform polyphonic note-based expression. But almost no keyboards support it, and ROLI created the MPE standard to provide a workaround by splitting messages across multiple MIDI channels. Interestingly, MPE has received quite a bit of attention, but this doesn't require a new plug-in format to support it. And ROLI, the company, has been disastrous in the marketplace by adopting Silicon-Valley-esque approaches, raising capital, growing too fast with needless acquisitions, filing for bankruptcy, rising more money, and it even has a leader who thinks he can walk on water!
So if I sound old-fashioned and against new ideas, nothing could be further from the truth. But to pretend musicians would jump on disruptive innovation just isn't what has happened in the past. Maybe this time it'll work, but I don't see that industry has changed all that much. In fact, in many ways it's worse. More and more sample library creators have created their own sampler for playback, so whereas Kontakt used to power most libraries, now Spitfire, Cinesamples, 8dio, Orchestral Tools, and others, have their own engine. The phrase herding cats comes to mind.
Diversity and change is the one thing that just hasn't happened in the music and audio world. For example, Steinberg introduced Nuendo 22 years ago with the intention of it disrupting Pro Tools... However, go to Skywalker Sound, for example, or any other high-end audio facility, and they won't be running Nuendo -- at least in the US. And as for open source, listen to Paul Davis talk about Ardour... For some reason, open source music and audio software has just never become a thing. And sure, it would be cool for there to be a kind of Red Hat model adopted in the audio industry, where money could be made from supporting an open-source-based ecosystem, but I think CLAP has more chance of succeeding than this reality.