I've read a few years ago an estimate revenue at $180/user/year in the US. Rest of the world was lower.

Many here would pay $5/mo, but probably only a handful would pay $180/year.

Now imagine the hundreds of millions they serve. Safe to say most wouldn't pay even $1/year.

Also, if Google loses even 10% or 20% of their audience, the overall value lost will probably higher due to network effects.