Diablo 2 Resurrected didn't pioneer them
Real-time payments aren't brand new by any stretch or imagination. Diablo 2 Resurrected didn't pioneer them, and it would be disingenuous to present that as truth. Blizzard's action RPG isn't the main of the problem, but instead is it's the most terrible amalgamation of free mobile and PC games. With two distinct Battle Passes each with unique rewards exclusive to a character (and not to your entire roster), and too many different currencies available for the average player to track, Diablo 2 Resurrected's economy reads like D2R Items a giant mobile market.
Even though they're sometimes received with apprehension they have been accepted as normal within the gaming industry in general. One could argue that popularity of loot box or other real-money transactions within AAA games have been a factor in this unregulated economy, but the more AAA gaming shifts towards the game-as-a-service model is the more it has similarities to mobile games that have been within this very popular sector for more than a decade.
And this doesn't just show in the use of paid currency to buy items however, it is also evident in gacha mechanics, and the disclosure of drop rates among uncommon items. Gacha is the practice of using in-game currency whether it's free or acquired by a shop in the game, to purchase something randomly items, such as equipment pieces for instance, in the case of Dissidia Final Fantasy Opera Omnia or characters from the ever-popular (and persistant) Fate/Grand Order or Genshin Impact.
In the case of Diablo 2 Resurrected it's the use of Legendary Crests (which can be earned or purchased) to increase the chance of a five-star gem appearing in the dungeons at the end of the game. While it's not completely conventional in its design (most gachas are played out by "rolling" in a limited-time banner) the players are engaging with the kind of randomness similar to. In many ways it is the case that Diablo is a classic Diablo series has been building towards these kinds of mechanics since its beginnings, in the words of Maddy Myers wrote a few weeks back.
Diablo 2 Resurrected also, in simple terms, draws direct inspiration from a "feeding" method that Japanese, Korean, and Chinese mobile games have adapted for over a decade. "Feeding" entails raising the stats, attributes or rarity of an item through creating duplicates of an item drop. The duplicates then feed to an item of the same rarity , thereby increasing the overall stats of an item. Generally there are five copies as a standard for maxing out a character or item.
My first experience with "feeding" was through Fate/Grand Order, which was first out to Japan in July of 2015. It made a profit of $4 billion dollars worldwide in the year 2019. In order to create a character that was the best that it can be I had to purchase copies of every one. Then, when a particular advertisement came along I was able to pay around 300 euros to get the five-star character I'd coveted throughout the years. However, I never obtained the replicas I needed to be able to appreciate the full potential of this character. With the average rate for top five-star characters being around one percent, it's an unsurprising that I did not manage to get a copy of the character while in the game (which I have since uninstalled). As of July 2021, Fate/Grand Order was the seventh highest-rated mobile game of Diablo 2 Resurrected Items all time, and was ranked behind Konami's Puzzle and Dragons. This, I might add, is also a gacha game.