(re: What about new sequels?) The way I see it, the Golden Age of adventure games lasted from 1987 – 1994. I believe those titles mentioned by Brandon were (and I reckon this is general adventure gamer opinion) of a lower quality than the Sierra product that went before. Thus I believe that where Sierra initiated the Golden Age, they were also the ones who ended it by releasing a whole clump of lower quality products.
Of course, this Golden Age weren’t only dependant on Sierra’s releases. It seems that many companies who were heavily into making and/or publishing adventure games at that stage released their best product during this time period as well. One can take a look at Lucasfilm Games/Lucasarts, Microprose, Revolution, Dynamix, Infogrames, Delphine, etc.
In the end, I reckon the heavy diversification of product that happened at Sierra in the mid ’90s was a huge mistake. But that may just be me. Their core market was still an adventure game market. But because of a loss of focus, their adventure games released in mid ’90s were of a lower quality than those released during the Golden Age. In a sense, I do believe this directly triggered the short-lived surge in popularity of RPGs in the late ’90s, and that of first person shooters thereafter.
I reckon if Sierra remained focussed on producing high quality adventure games (and thus allowing the market to retain a large percentage of gamers who were primarily interested in this type of gaming), instead of diversifying so heavily, the PC games market might actually have looked very different today.