Are you saying that if they don't provide these extra features, their advertising revenue will fall (due to reduced user base)? Because that's the opposite of what you started this thread by saying.
If you took the same concept and applied it to television then would it just be entirely advertisements? Who would watch it? Obviously there needs to be a balance between providing utility and earning revenue. And television is typically a service that users pay for in addition to having advertisements!
> But masses of people want to use them
Many products get popular by being high quality, lock in market domination as much as possible, and then maximize revenue even if at the expense of quality. Food brands often follow this trend by using high quality ingredients early on then go public and replace the ingredients with cheaper ones. Sure, eventually the brand loyalty is destroyed, but that can take significantly longer than it took to build the brand recognition.
> despite them not offering the extra features
Most search engines had this specific feature for most of their lifespan. It's difficult to tell if a search engine like Google would get popular if released back in 1999 while being operated like it is currently.
This whole thread has been a response to this:
> I don't think search engines should only be providing features that boost advertising revenue.
It seems you don't actually mean that, so I guess we probably agree.
They won't make this money if we don't use their service.
So, they may try to encourage us to use their service, even if that encouragement itself is costly in isolation from its effect. In this way they can ensure they continue to make money off of us by way of advertisement.