Long ass spergy -trust me bro- speculation post warning.
Cows come in many variants. I feel like most of the time, random chance and simply entertainment value is what separates lesser cows from the ones who “make it” (in the worst possible sense of that term).
Before the internet and as the lolcows of history section will clearly demonstrate, there has always been batshit, autistic, narcissistic, etc people. Most of them will never reach any meaningful exposure.
I would argue that all true lolcows have one or more mental illnesses and or personality disorders/ extreme traits. Whether or not they become recognized as cows depends on their pathology, whether or not they gain enough exposure, and whether or not their repeated interactions with their environment is entertaining or not. Note that entertainment value doesn’t necessarily mean funny. Causing any emotional response even if it’s anger can create engagement.
Finally the most prolific lolcows have a desire to be famous, and often act as the main driver of their public presence.
So imo any random schizo or narcissistic boss can be a potential lolcow. Cows tend to share common characteristics, but the unique expression of their pathology and engagement with their environment vary wildly.
The most prolific lolcows hit a perfect storm of factors that have made them popular:
Mental, and or personality disorders.
Entertaining engagement with their environment.
Self propagating exposure to the public.
A consistent belief in a warped perception of reality that prevents them from accepting any forms of accountability, self improvement and or treatment for their conditions.
A dedicated community of followers who are entertained by them, and thus indirectly feed into their delusions of grandeur.
And finally chance/ legacy. Pure chance plays a factor. Cows who got big early on have had a tendency to stay popular simply because they appeared to be uniquely batshit and funny when the internet first started to really take off. Think about it. The massive online presence today combined with SoMe has made the entire world painfully aware of just how many off the rocks people live amongst us in society. This used to be something that was primarily known within the world of mental health care and social workers.
Today we can all find 100s and 1000s of them on every conceivable platform out there using very simple searches. So the pool of cows is vastly greater now than it was in the old days, and it takes a bit of chance for a cow to be noticed.
And finally a significant variable today is previous exposure i.e. if you’re already “famous” / have some established public presence on the internet and then later turn retarded (think of Iddubz for instance) you almost automatically become a cow because you’re a known person.

In advance. I have just mused about cow “psychology” for a while and had the time to sperg so there it is.