There are definitely big players making a lot of money from plugins they develop. Here are a few to check out:

($1200) https://www.native-instruments.com/en/products/komplete/bund...

($300) https://www.soundtoys.com/product/soundtoys-5/

($500) https://www.arturia.com/products/analog-classics/v-collectio...

However, piracy is also pretty big when it comes to plugins.