Wow, who set the question? Is that inherent bias supposed to be an academic approach?
Perhaps 'relative decline in mass market appeal' but 'unpopularity'? Try telling that to Big Fish or Her Interactive. The games industry is up 16% on the year before in the middle of a recession and adventures hang on to their 6% share. They're not unpopular, it's just that people of a certain age and gender don't get to hear about them.
This is a market issue, not a player issue. Places to look:
1) The horrendous advances charged by console game manufacturers which force developers to spend millions marketing console games and thus to swamp retail shelves. I could show you a city game outlet with its entire stock of PC games on one rack next to the staff toilets
.
2) Absence of marketing channels. Take a look at the pictures of the editorial staff of any mainstream games magazine. Exclusively young and male. Totally unrepresentative of the gaming demographic, but the magazines dominate the readership with a very, very, narrow agenda. There is no print adventure specialist magazine in the US or UK. Actual average age of gamers is 35 and the gender split is even (NPD). The magazines and retailers do not realise they are ignoring the majority of the potential market.
3) The state of adventure publishers in the US is also worth considering. A number of them have seen their developer lists change dramatically, which begs the question why they can't hold on to their developers. One well known one last year - 42 games, 38 developers - everybody leaves. Why? Small firms, small marketing budgets, possibly tight cash-flow? Or something else?
4) The decline of the PC - popular in the 90's and early 00's with Email and the rise of the Web, the younger generation uses mobiles for those functions and plays games on consoles.
But it's about to turn round. See Steve Ince's excellent article at AdventureGamers. He contends the HOG is in decline and the adventure game will take over. We just need better distribution channels to replace the retail outlet, which fell off a cliff last Christmas.
Cheers
Noel
Arberth Studios