It's all about greed these days, so any coin that's extremely popular (even if it's a "shitcoin") will certainly gain the attention of big exchanges like Coinbase and Binance. For an exchange that used to have strict listing requirements, I'd say Coinbase has changed a lot over the years. It looks like Binance is eating all of Coinbase's "candies", as it continues to expand its operations worldwide. Coinbase wants to stay ahead of the game, so it will list as much altcoins as possible in order to prevent Binance from taking over the industry at its entirety. The fact that Coinbase added "SHIBA" as a new trading pair on its platform, tells us how desperate the company is on getting a piece of the pie.
You do have a good point on this. It’s quite possible that the reason why coinbase.com has been doing all these is because they are just trying to keep up with the pace. They now see binance.com as a competition and want them to take away all their customers, by having so many coins listed on their platforms. So, they are just adding more and more coins, even the ones that are necessary, on their platform, to be able to keep up.
The Coinbase that I know before usually don’t list so many coins on their platform, they only just provide readers with a few options on their platform, but now they are just listing almost every new coin that is trending in the market. I was even surprised that they listed Shiba Inu on their platform when it was announced on the news. I don’t even see the need of following these trends, because some of these coins usually end up useless.