What do I mean when I say a different mind-set? Hobby game players then (as opposed to mass-market/party gamers) mostly played games to overcome challenges and to earn what they received. Most players now, especially influenced by video games and free to play video games in particular, play games to be rewarded for their participation. In other words, consequence-based gaming is being replaced by reward-based gaming. People play not to gain something but to receive something. A secret door is not a situation to cope with or a clever obstacle, it's a dirty trick by the GM because it interferes with rewards. The old-school movement is one reaction against the newer point of view. My old view of D&D-as-wargame doesn't fit the newer point of view *at all*.
Lewis, first, welcome this thread, that's awesome! Second, with the greatest respect, I'm afraid this is utter nonsense. Two things jump out at me, as someone who has played TT RPGs since 1988, since long, long before F2P games or video games which rewarded mere participation (which, at earliest, can be traced back to the '90s), as obviously untrue:
1) You assert that there are these two opposed gaming styles - consequence-based, and reward-based, and that there has been a move from one, to the other. Unless you are claiming that this change happened prior to 1989 (and thus cannot have involved F2P games or the like), this demonstrably false.
Many people play RPGs neither to experience strategic/tactical consequences, nor to gain rewards (magic items, levelling up, and so on), but basically because they love the social experience of RPing. The success of games like Vampire, which isn't really about either of strategic/tactical consequences, nor about rewards, but more about the experience, is incredibly clear evidence of that.
Further, even if we accepted this consequence-reward track (which I don't think we should), most gamers are going to fall somewhere in the middle.
2) You assert that playing games "for rewards" is something new, that is "replacing" consequence-based gaming. This is completely wrong, I would suggest. The first D&D group I saw which was not my own, in 1989, was entirely about rewards. It was about magic items, gold and XP. No-one was interested in RP or characters or really in the world (even things like becoming a king or whatever tended to be forgotten in the pursuit of bigger and better rewards), nor were they interested in "consequences". This was older players, playing 1E, and who had been playing it since the early '80s.
Nor was this uncommon at all - I saw, heard of and read about many groups doing the same thing - basically playing D&D as a game to rack up a score - sometimes the DM would be sort of involved in helping them rack up the score, which usually got called "Monty Haul" gaming. (In fact the vast majority of 1E and '80s RPG-only groups I came across were like this - it was 2E groups and non-D&D groups who tended to be more interested in telling a story, in my experience.)
If you got these people to play an RPG where they couldn't rack up some kind of score, they rapidly got bored.
Remember, this is in the late '80s and early '90s. Computer games back then were quite punishing, typically, and whilst score-oriented, certainly didn't reward one merely for playing, and there were virtually no F2P games in the modern sense.
3) "Secret door is a dirty trick" - This is an interesting example on two levels - first, I first heard complaints about this sort of thing from said 1E group, in 1989, and second, it only makes sense in the context of a kind of score-based game where rewards are hidden behind the door, rather than a plot-based game. I can see from your comments thirty years ago, that, then at least, you studiously objected to plot-based games (such as one centered around a pre-determined mystery, for example Trail of Cthulhu), but that doesn't mean that someone objecting to a secret door that is found merely by chance and has no clues to it's existence is "demanding rewards" - he may merely have different expectations about how RPGs work to you (as I think virtually everyone does).
So, anyway, as someone who has watched RPGs evolve since the 1980s, I really don't think there is either a consequence-reward change, nor do I think that everyone you think is playing merely for "rewards" actually is - I think you're misperceiving other motivations entirely for gaming, and ignoring really, the whole evolution of RPGs through the '90 and '00s.