The vast majority of web content has zero security relevance. Who [i]cares[/i] if that cat picture is sent securely?
Do you like your web traffic to have ISP-injected advertising added to it?
Do you enjoy having your ISP add uniquely-identifying tokens to every page request?
Do you enjoy not knowing whether that file you just downloaded from $reputable_site has been tampered with?
Do you like receiving web pages which could be trivially rewritten to directly contain malware?
I don't. That's why I prefer the authentication and privacy offered by TLS.