The NSX is (unfortunately) becoming a collector car. Part of that transition is Honda making the choice to discontinue certain parts, and it means that we must come to terms with not everything being available at the Acura parts counter.
But the situation is still really good! The NSX is still the most well known halo car of the brand, so Honda has been slow to cease production of necessary parts. We have strong vendors (SOS, Mita, others) who are making investments on improving the OEM parts.
The community is great as well. There is an absurdly high number of engineers, racers, and, creators who continue to expand our knowledge about how to maintain these cars and drive down the cost of ownership. Examples that have occurred since I got my car in 2016:
-The S2000 ABS modulator as a replacement for the original boat anchor
-Heineken's ability to service the OEM radio, along with instructions here on Prime
-The group effort to crack the ECU and allow for tuning using OE components
-Multiple well-documented gearbox rebuilds right here on Prime
So don't compare parts availability to a new car. A better comparison is against other aging super cars and exotics from the 80s-90s. I think the NSX, and the community around it, continues to stack up very well.