Being a player that can reach high ranks with relative ease on a consistent basis over the years I can give some insight from that perspective.
Basically, it’s gotten progressively harder to reach high ranks putting in the same amount of time year over year. That anecdote is consistent with the games RNG deciding more and more of matches over time. This is actually fully expected as power creep… Creeps forward.
If you follow any of my posts on these topics in the past you will already know this from there, but I will repeat myself somewhat here to keep things self contained.
First, in any game that mixes randomness and skill, skill is never truly removed out of the equation. Instead, as randomness increases, you should expect many more trial repeats to obtain the same level of confidence on any statistic you wish to measure. What does that mean? That means as RNG increases in the game, it takes many more games for your skill level to make an impact on your winrate.
Next, Hearthstone will always have a fundamental component of randomness in it related to card draw. This, combined with power creep year over year, means that drawing the cards you need to win in the correct order has a larger and larger impact on winrate as power creep increases steadily. Therefore, the games randomness steadily increases with power creep!
Hence, what we will eventually get as power creep continues unchecked is a game where skill will matter after ten million games, but not a game before that. What does that mean? Well theoretically skill still matters, it just only matters if you can live as long as the solar system.
Translation: there are limits to the amount of power creep and randomness that a card game can carry before effectively being a completely random game for humans, but not for stars (the solar system kind.)