Yes, they really miss the opportunity to get a foot into many smaller companies and scale up. For anything useful you need at least $10k/year (likely more), but what if you only need a tiny feature in addition to the open source software? Then this pricing feels just too much (although they of course have to financially support the open source software too) and it'll be very likely that you try to solve it with the open source nginx.

If they have modules - why not sell these modules and attach a "reasonable" price to it?