track_io_timing default setting

Can we change the default setting of track_io_timing to on?

I see a lot of questions, such as over at stackoverflow or
dba.stackexchange.com, where people ask for help with plans that would be
much more useful were this on. Maybe they just don't know better, maybe
they can't turn it on because they are not a superuser.

I can't imagine a lot of people who care much about its performance impact
will be running the latest version of PostgreSQL on
ancient/weird systems that have slow clock access. (And the few who do can
just turn it off for their system).

For systems with fast user-space clock access, I've never seen this setting
being turned on make a noticeable dent in performance. Maybe I just never
tested enough in the most adverse scenario (which I guess would be a huge
FS cache, a small shared buffers, and a high CPU count with constant
churning of pages that hit the FS cache but miss shared buffers--not a
system I have handy to do a lot of tests with.)

Cheers,

Jeff