More and more people understand the concept of short life span humor and things, on a digital scale.
Many things we interact with we throw out after single use or a few. Humor is only now being seen as such by the masses. If you read some of the old greek plays, they are still a riot and amazing works of art. Now some of those don't age well and others we flat don't get due to loses in history.
Back then one of 100 people could write or read, now almost everyone of 7 billion plus people can. So just more people to make more content, and some people aim to make long lasting humor others don't. Some things catch others don't.
Memes just go with social trends, like slang really. It's always changing and will keep going but some stuff will stick around, but while "cool" as good even my 89 year old grandma knows for spoken word that's pretty long, pepe is 3 years now, for net that's long. Will pepe be known of in 5 years or funny/relevent? We just don't know. It's also up to society if none of us wanted to say cool anymore it would not have a meaning aside cold.
There's a lot of jokes about meme wars etc, but memes are really just slang and quick current humor they mean nothing and everything. Older memes like early 00 had a different culture and smaller base so the memes were different in style as well as humor.
If you don't like or do like a meme don't stress it it won't last and that's part of the game. Think about how many one hit wonders are out there, memes are just like that but even less invested and no real economic gain vs that one dude from American idol who sung really bad and wound up selling a few million CDs. See that was less than a decade ago and I have no idea his name, we went a whole year the western world laughed at and with this dude, he's a multi millionare from it too probably. Wojack made probably 40 bucks as some art student drew it for a nerdy kid to cover ramen and a bar bill and was hung in a dimly lit dorm.