For years - decades - PC gamers played games whose entire data footprint was less than a single texture of a modern FPS. Ultima, Elite, and many other classic games were programmed by one person, and after compiling take up about 300 kilobytes of space. It really isn't too much to ask that modern game developers - with their million dollar budgets, 50+ teams of people, and liscensed technology, at the very least match the gameplay complexity of what amateur hobbyist programmers could achieve in their garages 20 years ago!
So I totally disagree with your "appeal to authority" - modern game developers think gameplay complexity is unfeasable in modern gaming are full of shit. As long as they can afford to hire 8 man art teams, expensive voice actors, buy newer and more powerful computers and so on, they can afford to consider the level of gameplay options and complexity that System Shock had in 1994.