Directing into a variable doesn't work

[Peter Passchier]

With memory being abundant and filesystem access expensive, I want to
put stdout and stderr of a command into variables (without needing to
write to a file):

output=$($command 2>>>errors)

Or:

$command >>>output 2>>>errors

Obviously this gives a syntax error now, as this intuitive idea isn't
implemented (yet). Any chance for a fix, to introduce an operator >>>
that functions as a "reverse here-document" that stores the content of a
file stream into a variable?

I think that would be very useful extension, easy to comprehend in the
light of current syntax, and not clashing with anything existing as far
as I can see.

Peter