The mobile browsers aren't the problem, the content (read: advertising) is the problem. Loading tons of ad images and tracking scripts is what makes it shitty.
Mobile web browsing without an ad blocker is miserable compared to the same thing on desktop. At least on the desktop you've probably got 1920x1080 or 2560x1440 screens, more processing power, more RAM, and a connection that offers more than 5GB of data each month. With mobile it's unbearable.
I'm not saying kill advertising, but they could control it so that only a set number (2 or 3) ad scripts could run per page, not the 10-15 that is common nowadays.
Well, I do say kill advertising :)
Of course radio and TV are the same way. Mass media has always been a race to the bottom where producers race to out-do themselves on offering 'free' content of absolute minimum quality to occupy someone's time and get ad dollars. Listen to the absolute shit that fills free TV and radio airwaves.
Market dynamics are complex and the wants of the uncoordinated many are usually override by the wants of the coordinated few. For instance, Microsoft wanted core competencies of the competition to be free. So it developed Internet Explorer and bundled with every Windows system. The wants of the people weren't relevant.
You get what you pay for, therefore it is shit.
This implies a correlation between money and quality, which not always holds.
Some things are free and aren't shit. For example: Linux
Some things are made shit when they aren't free. For example: many scientific papers .
Things that require effort usually require an incentive. Money, specially paying for use, isn't the silver bullet of incentives.