Nah, we are not anymore. 
But yeah, you are right. However 100k$+50$ resin vs 3.5k$ + 150$ resin and you can still print a lot with the last one before you get break even.
That being said, I tried several 3rd party resins but formlabs is still a step ahead on printing quality for engineering applications. For figurines and big/course parts these 3rd party resins are fine. FDM is a no-go.
A few years back on an open source forum there was a list of chemicals for a basic 3D printing resin. If I remember correctly the cost per liter was about 30 USD. But don’t forget that development of resins is costly. It requires a lot of testing and experienced chemists and they don’t come cheap.