I think we are absolutely in the golden age of pinball right now. Sure more games were sold years ago but I don't think that automatically makes that time the best era.
The designs, use of technology, code, animations, music, etc in games today is leaps and bounds better on average than what existed 20, 30, or 40 years ago. Also, the pinball community is more connected than ever today thanks to the internet with sites like Pinside, multiple pinball podcasts, people streaming games such as Dead Flip and Buffalo Pinball, and Stern heavily promoting on location play. We even have a live award show at a huge pinball event, the TWIPYS at TPF, with staff from multiple companies showing up to celebrate pinball together. Pretty much every game being announced right now looks awesome and there's so many titles to choose from and from multiple manufacturers. This is an amazing time for pinball and I hope it doesn't end anytime soon.