There was a C++ dev kit eventually, but only for drivers (though some people figured out how to use it from NS). I also did a “native NewtonScript” compiler that under the hood compiled NS to C and encapsulated the native code into a NS function.
What really freaked people out was the 1% (?) royalty on apps, which I don’t think lasted long. Now of course Apple gets a 30% royalty and that’s considered normal! (I should mention that we wanted to have a Newton App Store, but you would have accessed it by modem, of course!)
The 2000 had the StrongARM processor that ran about 10x as fast as the earlier models. That was really the first hardware that gave something like the experience we were trying for.
I remember there was a C++ dev kit eventually but at that time the momentum for Newton was already gone.
It makes me kind of sad thinking about this. I think with today's connectivity and processing power combined with the ideas of the Newton devs we could have much better devices than what we have today. The iphone feels a little boring. Well made but boring.
Even the Palm SDK was commercial in the beginning. But a free toolchain was put together by some hacker after a year or so, which subsequently convinced Palm to lower their price and eventually give it away for free IIRC. Then again, even VisualC 6 cost 400$ or so back then.
We just weren't set up to do a C++ SDK; too much of the system wasn't documented, or designed with third parties in mind, and frankly a bunch of it probably would have had to be cleaned-up in order to be usable by outsiders. Native debugging was done on expensive, hand-built and very specialized hardware ("bunwarmers") which were NuBus-attached boards with a bunch of static RAM and some other things unavailable on the real hardware, and we would have had to do some tools work to make that usable outside as well. There was a serial debugger (substantially ARM's) but it wasn't a great experience.
There never was a coherent installable driver story. That's probably my fault, we were writing code really, really fast without a lot of time for platformy conveniences (that "platformy" stuff was mostly at the NewtonScript level, with Walter, Capps, Martin Gannholm and some many other folks I've unfairly left out). So things like third party PCMCIA support would probably have needed an overhaul.
The 100 version of the Newton was not very good but the 130 version and then the 2000 were really nice. Also I think Apple should have been more forthcoming with a C++ SDK so people could write own drivers and implement stuff that needed more performance. NewtonScript was just damn slow.
I still like playing with my Newtons from time to time. I also have a 2 MB storage which cost $200.