I don't actually think the rush for RPs is the main reason for this striving to reach pro rank.
RPs are just an addition to that. A kind of important addition, especially for people, who do not have their reward books completed or full cards collection. It's a Collectible Card Game after all, and people like to collect things. But as soon as the goal is fulfilled, the RPs just keep stacking up without having any use any longer. That's what most people have faced or will face sooner rather than later, given that the game is literally bombing players with RPs.
Exactly. I have a feeling that many people just have this need to be as high as possible in the ranks, maybe they want to be perceived as good players, but this is often under a false assumption, that the rank is the main indicator and reflection of that. As a consequence they tend to limit themselves to just 2-3 decks, that they get the biggest winrate with. There are many videos on YouTube, where pro rank players simpy do not know how some cards work. And this is because of what you mentioned - they did not take their time to learn the game. All in all, the conclusion is always the same - netdecking is not doing them and everyone else any good.