Most of the new bitcoin people have used the wallet because of the word "blockchain". I've used it before when I was a newbie because I thought it was the official bitcoin blockchain wallet because of the domain. 
You are right, When I first got to know about Bitcoin. The first wallets I signed up where web wallets and guess the names... Blockchain and coinbase 
I think the fact that the web wallets use an approach that most newbies are familiar with (signing up with an email and password), most of them end up getting trapped by the web wallet leaving behind noncustodial wallets that seem a little more technical to set up.