Well, PhotoPost is 12,000+ lines of very optimized PHP code. The team of developers that creates and supports the product has to eat. Why is it okay to pay for a good forum but not a good gallery? If someone wants to write a hack that does the same thing as photopost, be prepared to not sleep for the next 5 months..
Anyway, it really is a great product and it's getting better every day. vBulletin is the best forum out there IMO, and PhotoPost compliments it well.