I don't think most recent AAA games count as "challenging", the tendency has been going in the other direction for a while, minus accidents like Dark Soul. I'd

I don't think most recent AAA games count as "challenging", the tendency has been going in the other direction for a while, minus accidents like Dark Soul. I'd say it's mostly about the budget, and as Hollywood demonstrates regularly, it's extremely easy to create a flashy but ultimately mediocre product with a huge budget. Not to say that all AAA games are like that, of course (eg, Alien Isolation looked pretty decent).