I can almost see validity in the points he's trying to make here but I think he got caught up in trying to do it in a clever or shocking way to engage the audience (both present and extended) then in doing so didn't fully analyse some of his claims.
It is true that the concept of "core gamer" as a multi use definition that has grown less significant as the variety and availability of games grew along with the wider and more diverse base of gamers.
I find myself thinking that the concept of a "core gamer" should actually vary based on the studio and the title they are working on, rather than be some prepacked concept that defines gaming as a whole.
Even so, there seem to be a number of assertions that just feel faulty.
Size of demographic is obviously relevant to developers but can't be considered without also factoring what individual elements of that demographic are willing to soak as expenditure.
The free to play market recognizes the difference quite readily between those who dip into their games paying for nothing save with add views and those who throw dollar after dollar into the microtransaction money mill.
The same level of demarcation has to exist between a gamer who will buy a new title every three months on the app store and one who purchases at least one title a month at around the sixty dollar mark.
Failing to recognize that is akin to ignoring inconvenient data.
As stated above by NPC009, time is a more relevant factor in how many games you have on steam.
Having more or less does not indicate what kind of gamer you are, just how long you've been playing games.
I'd also contest the claim that owners of many games are seekers of novelty.
That may be an aspect of what drives a sale and it may be a motivation that an individual sometimes responds to, but it does not follow that size of library is an indication of this, nor what title said customer desires at that time is an indicator of seeking novelty in their gaming experience.
It is very possible to have a library full of nothing but strategy games, fps, rpg etc, etc and beat that arbitrary ten.
When I want a novelty, something fun but short lived as games go, I head to the app store and pick something up quite cheaply.
Or even free for that matter.
What I find there always seems more fitting of the term 'novelty' when applying it to games.
I also wonder if the worth of the demographic varies per developer.
Larger, more expensive titles require a higher investment of time and money to achieve the perceived standard expected, whereas a five dollar game on an app store requires less investment financially and while the individuals who work on it will work just as hard as the larger developers (in theory) they do make up a significantly smaller team and the final product requires significantly less man hours to produce.
Ergo, to the financially minded developer a game that requires low man hours, low investment but has the potential to turn a result like, for example, Undertale could be seen as much more desirable.
Therefore, the demographic attracted to that game would also be more desirable.
One could even say that they are the developers "core" audience of gamers...
While It's fair to say there's a lot of things being said by this speaker that I don't agree with, either based on reasoning gaps or conclusion, it's certainly been a topic that's got me ruminating over it and by that metric it has succeeded.