I still have it in fact, I don't like how power hungry it is but it doesn't really matter for the very little time that I watch TV (which is mostly during the day in the weekend, when my electricity is self produced solar anyway). That said it's probably time to get a new OLED TV and I am just waiting for the day that I will need new furniture.
If you had one with 100 nits, you got defective unit.
Even the best plasma TVs could only reach just over 100 nits of peak brightness in a 10% window test.
But the article also compares them to todays LCDs with 1000 nits. LCDs at the time weren't so bright either, they were about so bright as plasmas, but unlike plasmas, they also were gray goo.
So if they measured some 10-15 years old panel that spent most of its life being turned on, there's your answer.
There was not much overlap of consumer-priced plasma and OLED panels.
Lots of those Pioneer/Panasonic plasmas all had "hidden" service menus that allowed people tweak/calibrate all sorts of picture variables to their hearts content as well, which rightly or wrongly, probably also helped give them a certain love within cinephile type groups.