Logs are typically off by default in most Enterprise software, or goes nowhere by default which is basically the same thing.
Logs cost money to both collect and store. Not everyone is cheerfully burning through VC capital. Some people have budgets.
Speaking of log collection, simply dumping the logs into a central repository is the same as taking the garbage to the landfill. Collecting trash just results in a big collection of trash.
Extracting useful information from a huge pile of logs is non-trivial. You'd have to know at least one query language, probably several if you work on big enterprise systems. You'd have to know a bunch of esoteric things like how to convert the long decimal strings to a number so that you can interpret as any one of a dozen timestamp formats as an actual datetime in UTC, and then convert that to local timestamp so that you can tell when something actually happened. And so on.
All of this is merely a prerequisite for finding a specific instance of what you know is there.
You know what you'll never find in logs? Things you didn't know to look for! That's unfortunately about 90-99% of what you actually need to know, making logs typically about 1-10% as useful as you'd like.
Did I mention they cost money? Have you seen how many arms and legs Splunk charges these days? Why would you pay that much for something that is less than a tenth as useful as it could be?
The fundamental problem is that discipline doesn't scale. You can't expect a hundred thousand IT operations guys to all do everything all of the time, in spite of the non-technical finance guy holding on to the purse strings like he's gripping a life preserver after going overboard in a raging storm.
PS: I turned logging on extensively for a recent Azure project. Some logs cost more than the service they were monitoring. I mean sure, I could turn off the unnecessary logs, but how do I know ahead of time which ones will be necessary or not? I don't have a time machine! I can't go back and turn off the logs I won't need... later.
PPS: Have you noticed all logging companies charge by the gigabyte? What incentive do you imagine they have for improving the efficiency of the log transfer and storage formats?