In the early days of video games, games did not remember you. When you started another game of Tetris or PacMan, you started in exactly the same state as your first game. Any "progression" came from what you had learned in earlier games, from you getting better at the game. But that sort of learning curve becomes slow after a time; yes, your 1000th game will score much better than your first, but you 600th will not necessarily feel much different from your 500th. But as players liked progression, and technology advanced, games acquired the ability to remember you and to boost your progression: Playing a game would not only make you better at it, it would also give you some reward like a bigger gun or experience points / levels which would make the game easier for you.

Players *really* like progression. While Progress Quest in 2002 was meant to be a parody, a game that had only progress but no gameplay, that sort of idle game actually became a genre. More importantly the mass market for mobile games is full of games in which the gameplay part is fundamentally very easy, and artificial progress, which can then be monetized, makes up most of the game. That led to some backlash with an endless discussion on monetization, Pay2Win, loot boxes, and the like. However that discussion only made the distinction between monetized and not monetized progress, not between progress by learning and progress by receiving virtual rewards. Most players are still totally content at getting visible and measurable progress in a game through "grinding rewards", even if they don't actually get better at the game at that point.

To me that "playing for progression" is losing its luster over time. At some point the brain's capacity for pattern recognition kicks in and dampens the dopamine effect of "shiny reward -> joy". I don't know in how far that is a universal phenomenon. But when I hit the typical "pay or grind" wall in a game, the question for me is less about which one of those options to choose (I might go either way), but rather whether the underlying gameplay is still interesting enough for me to want to continue at all. I currently play World of Tanks because even a battle of tier I tanks is fun gameplay and I am still learning with every battle. I am mostly playing tiers IV to VI (because the campaigns don't work before tier IV), and I am in no way impatient to progress to the higher tiers (which I easily could due to previously acquired rewards).

If more people felt like me, that would be somewhat of a financial problem for game companies. Artificial progress is much easier to monetize than fun gameplay. But I would say that fun gameplay is a necessary condition for longevity of a game, and so game companies should in any case make certain that their games are fun to play before trying to wring the last cent out of their players.