I don't buy into this one sodding bit.
It's not about being able to produce content and "support", it's just a way for them to make extra cash off of people instead of putting out actual content that people would be willing to pay for. Consumers have shown publishers it's much easier and simpler to just create a micro-transaction or lootbox centered system than it is to create content that gives people a tangible reason to give them their money that isn't "You'll get this thing now instead of in an indeterminate number of hours!" Not only are they getting your $40-$100 - depending on the publisher and what fancy version you buy - they're also getting a few extra dollars here and there from some players, and making double, triple and much more off of others - the so-called "whales". With the amount of money they're drowning in from shit like this, of course they can squeeze out an extra map or two every so often. They could instead spend time to create something that actually adds more to the game to also draw in new buyers. Instead, we're saddled with AAA pricing with an extra monetization scheme in which consumers throw money at publishers to not play the game in some cases, and in others, to unlock content that is otherwise inaccessible for no good reason, and incentivizes the creation of new content just to lock away in loot boxes and/or force the player to spend multiple hours - or even days - to obtain a single item. Overwatch event skins, anyone?
Blizzard skates by on rather thin ice because everything in Overwatch's lootboxes are cosmetic and there's credits to outright buy cosmetics, but they're still on very thin ice. Heroes of the Storm is pushing a more aggressive attitude with lootboxes because the game is F2P, but it used to be that all cosmetic items - save a small few that could be bought with gold, which was also used to unlock Heroes - were cash only until Heroes 2.0 was released and they added a bunch of unnecessary cosmetics to pad out the introduction of lootboxes to the game. Hell, in the upcoming big overhaul of Heroes of the Storm, there's going to be "Gem only" cosmetics - with Gems being the game's premium currency - meaning you cannot buy those items with the secondary currency - Shards - that was introduced in Heroes 2.0 even though the sole purpose of Shards is to unlock cosmetics, in a game that has hundreds of cosmetic items.
Now, as a F2P game, HotS gets away with more simply because there is no entrance fee to it, but pay-to-play games don't get any excuses for lootboxes or micro-transactions. Especially when games decide to double down on a leveling system plus lootboxes/micro-transactions. The game industry was doing just fine without micro-transactions and lootboxes a decade ago, aside from the advancements in technology and game development, and corporate culture evolving, not enough has changed since then to suddenly necessitate the ham-fisted milking of consumers' wallets.