I see writing a book is no guarantee for possessing reading comprehension. If you read the part you quoted, you will see that I already listed what you brought up as characteristic of the new period:
Lots of new talent are moving into CRPGs, aided by digital distribution. Tons of new CRPGs published every year, with steadily increasing quality.
I read what you wrote. You listed 2018 as the time it began, just because it has the game you like, despite all those vital characteristics being noticeable since at least 2012.
And I would argue that "they finally made a game in an "old" style that is equal to or better than the greats of the previous era" is a pretty damn significant milestone.
No, it is not, because it's 100% based on your tastes.
aweigh here loves Elminage Gothic, a game that's "equal to or better" than old Wizardry. I think Tales of Maj'Eyal is the best roguelike ever made. A lot of people think Path of Exile is the best Diablo-like game ever made. Not to mention the tons of people who think games like The Witcher 3 or DOS2 are some of the best RPGs ever.
Yet you are so fucking self-absorbed that you go "No, the game that
I like is the sign of a new era!". Grow up.
So how would you periodize CRPGs?
I wouldn't, because I think it's something masturbatory and extremely short-sighted. All the ups and downs CRPGs went through are the same that the rest of the industry had.
For example, you can place Adventure games and CRPGs side by side and the evolution will be pretty much the same, because it was dictated by the context of the time. The arrival of the Amiga and other new computers in 1985 brought in better graphics, mouse-driven interface, sound and a huge leap in capabilities for all game genres. The death of all mid-sized game companies in the late 90/early 2000s left an oligopoly of a few mega-publishers and had a terrible impact on all game genres. And so on.
Listing those changes is what I did in the book, and it's a lot more interesting and valuable than arguing the subjective quality of games.