To latch onto this remark; indie games of today are bigger and better than the AAA games of 20, 30 years ago I think. Groundbreaking games like Commander Keen (side-scrolling on PC) were written by a late teen, early 20 year old John Carmack, who continued to basically invent 3D video games.
That said, reasons why indie games are better than old "pro" games are that they stand on the shoulders of giants; Carmack for example had to invent and apply a lot of theoretical knowledge into performant code, afterwards people could reuse his code and ideas. Programming languages and tooling have improved, so indie developers can focus more on building a game instead of solving lower-level problems.
But they still build their own engines, albeit usually not from scratch. I'm thinking games like Factorio, Cogmind, The Witness, Minecraft, Amnesia, Project Zomboid, etc (yeah I had to do a search to find and confirm these games).
That said, "high-end gaming" is a difficult term to use; with some of the most popular games, graphic fidelity and the like is secondary to gameplay. Minecraft, the best-selling game of all time, was made by one guy / a small team, Stardew Valley by just one guy, and Pokemon and Terraria were made by just small teams.
Nowadays yes, you get the occassional Battlebit and Vampire survivors which would make most AAA games blush in terms of sales, but in terms of scope they aren't anything like Assassin's Creed or Diablo 4 - that's not to say that they are worse, obviously not - just that it's impossible for a small studio to deliver the same scope as AAA studios with 1000+ people per project.
I think it's to a large extent due to the professionalization of the industry (even indies/small scale) and overall raising of the bar of expectations.
Back in the day, the divide was much smaller. So it was a lot easier for a motivated indie dev to make something like Crash Bandicoot and have it be seen in the same light as AAA studios.
Today, the divide is so high that you can’t possibly make a AAA level game as an indie. But a lot of indie games get overlooked by the mass market.
So I don’t agree with the author. Plenty of people start young, and possibly even more do so now than ever before. It’s never been easier to make a game.
But it’s also never been harder to make games that meet people’s expectations of high end gaming and that’s likely what the author is seeing.