In history books, different eras of time are categorized by historians into "ages", where they group years of time together based on a common trend. For example, you have the dark ages when civilization broke down somewhat after the fall of Rome, which was followed by the Renaissance when science and art blossomed. Applying this concept to Disney's Hollywood Studios is no different (although admittedly less epic) and let's group the years of Disney's Hollywood Studios and see what ages we come out with.
In history, antiquity is referred to some of the earliest parts of human history when civilzation was established with Greece and Rome. With the Studios, the creation of the Disney-MGM Studios and its first few years can be looked at in a similar manner because this was the the honeymoon period for the Studios. The park was brand new and it had as much attention as any new theme park could want.
The early years saw some attractions that were only around for a few years but they were unique because at the time, Disney was doing everything it could to draw guests in. The "Star of the Day" brought a different celebrity to the park for a motorcade and hand print ceremony. The Backlot Tour was at it's greatest length ever and had the most to see. You also had some new attractions that opened up such as Star Tours in 1990, Here Come the Muppets in 1990 and MuppetVision in 1991. With everything the Studios offered this was the classic time for the park.
The success of antiquity brought about a radical new change by 1994 and that was the expansion of the park. The Studios were so popular that Disney opened up Sunset Boulevard and over the next few years, added new attractions that have come to define the park as we know it.
The Tower of Terror changed what we thought of when it came to thrill rides, followed by Rock 'n Roller Coaster in 1998. Rock 'n Roller Coaster was a radical departure from what roller coasters were at Walt Disney World and it remains one of the most popular thrill rides. Finally, Fantasmic! opened and added a night time show that the park needed to distinguish itself.
In addition to the Sunset Boulevard offerings, you still had the classic Studios attractions going at full steam. The Backlot Tour, though broken up into a few smaller attractions, was still showcasing real production work. Superstar Television and Monster Sound Show were running and the Great Movie Ride never looked better. This time in the history of the Studios would prove to be the peak of what the park offered for a long time.
The dark ages for the Studios didn't come swiftly, it was a downward trend that began in 1999 with the closing of two opening day attractions that year: Superstar Television and Monster Sound Show. They were both replaced by attractions that many Disney fans can say in retrospect were not nearly as good: Doug Live! and Sounds Dangerous.
Things only got worse as the years went on, the park started to languish with closures and in some cases no replacements at all. The real big blow came in 2001, when the economy of the United States took a hit following the tech bubble bursting and Disney wasn't immune to the effects. Disney's decision to stop traditional animation was a death knell for the Studios. Its animators were laid off and whatever real Hollywood productions were still being produced in the park all but disappeared from the park. This left the Backlot Tour and Magic of Disney Animation relatively useless since their main attraction was gone.
In the following years, more attractions left and were not replaced, such as the Hunchback of Notre Dame stage show. There was very little positive additions to the park during this time, with perhaps the notable exception being Who Wants to Be A Millionaire - Play It!.
Things changed for the Studios in 2005, when Walt Disney World and Disneyland celebrated the 50th anniversary of Disneyland's opening with brand new attractions in each of the parks. The Disney-MGM Studios receieved Lights, Motors, Action! Extreme Stunt Show, which hasn't turned out to be the biggest attraction for the park but it kick started a rebirth for the Studios.
Following the addition of the new stunt show, there was a flurry of activity for the park in the following years to help fix the voids that had opened up. In 2007, we saw more closures to make way for new additions such as the closure of Who Wants to Be A Millionaire - Play It! to make way for Toy Story Midway Mania and work starting on the old Superstar Television building to bring the American Idol Experience.
In 2008, the Disney-MGM Studios was renamed to Disney's Hollywood Studios and we saw the opening of a number of new attractions that have come to define the park to a great extent. Toy Story Midway Mania opened in 2008 and quickly became one of the most popular attractions in Walt Disney World. The American Idol Experience opened later that year and offered guests a new type of experience never seen before. 2008 also brought us Block Party Bash, which is arguably one of he best parades to ever grace the Studios.
Star Tours was refurbished and opened back up in 2011 with an experience that most fans agree is a superior ride to what we once had. Certainly the trend we see in recent years points towards a direction for the Studios that many fans would be happy with. The days of empty buildings and "half day park" notions seem to be a distant memory, with more experiences and entertainment coming to the park each year.