If we are beginning at 2006, and ran every year without interruption, the 20th anniversary would be in the year 2025. However, 2020 happened, so the 20th anniversary would be in 2026.
When discussing a Hollywood anniversary year, it's crucial to consider what Hollywood's approach has always been. The focus has consistently been on marketing the event based on the current year rather than highlighting the years it has been in operation - which is more straightforward for the general public. In contrast to Orlando, which promotes its years of operation and leverages a rich history for a nostalgic appeal to help boost the excitement, Orlando can pull off an anniversary year much easier than Hollywood. Maybe when 2026 comes around they could, but I also don't know how interested Hollywood would be in the anniversary year. Incorporating the pre-Murdy era into the equation further complicates matters for various reasons...
ALSO - I do not know what difference an anniversary year for Hollywood would make when they usually do bring back a lot of their biggest original characters and ideas - Hollywood Harry, La Llorona, Hoildayz in Hell, Pandora's Box, etc.