This has never been an inexpensive hobby. However, prices have definitely outpaced inflation. I do remember paying $19.99 for medium to large sized yellow tangs back in the day. Corals too are super expensive vs 10 yrs ago. Not only have prices gone up, frag sizes have shrunk. What some might consider mini colonies now were good sized frags back in the day. And I don't recall paying per polyp all that often.
On a positive note, higher prices ensure that there is money being invested in captive propagation, etc. Given the regulatory environment, we will continue to see restrictions on wild caught livestock. From a sustainability and hardiness standpoint, not necessarily a bad thing. The downside is it is probably driving some folks out of the hobby.