Modern AAA games are incredibly expensive. This isn't a few devs doing late nights for a few months, it's hundreds of designers, artists, level designers, developers, testers, marketers, and more for long timelines. All of those people need plenty of hardware, and they all collect salaries and (hopefully) benefits.
You can't just quit your day job, live off your savings for a bit, and make a game like this. You need a big team with funding set up ahead of time, and that finding won't be released - either by external investors or management at a studio - unless you expect to make a return on that investment.
"Artificial scarcity" - which here is code for in-game ads and DRM - helps encourage people to purchase the game and guarantees revenue even in pirated copies. It doesn't mean guaranteeing the game will eventually break, but it does mean guaranteeing it will get a certain number of sales/revenue for a period of time.
I was active in gaming in the early-mid CD-ROM era and saw this in practice. If something can be trivially pirated (copy the files on the disc to a new one) it will be copied like wildfire. If it takes a bit more effort (bad sectors that make naive copying fail, etc.) then piracy won't go away but will become rarer. As the effort to pirate becomes more intense, if buying it is easier people will. If ads let you drop the price to a point where it's more affordable, more people will choose to pay it. Etc.
Games are also in a weird position compared to other things that are expensive to develop, because a large fraction of their target market either doesn't have a lot of disposable income. Adult gamers with lots of money are probably not abundant enough to justify raising prices.
That said, I'm not sure "artificial scarcity" is the right way to think about this. No company is making money off of five year old games. The fact that they connect to an ad server has nothing to do with creating artificial scarcity, it's just another revenue stream for the game company.
You can't just quit your day job, live off your savings for a bit, and make a game like this. You need a big team with funding set up ahead of time, and that finding won't be released - either by external investors or management at a studio - unless you expect to make a return on that investment.