The old days...
First of all, having actually flown some of the old straight-pipe 4-engine aeroplanes (B707 long body series), reverse didn't really do all that much 'reversing'...just made lots of noise...to the disgust of airport neighbors, no doubt.
The real problem with these old engines was the excessively long spool-up time, so pouring on the coals for a balked landing once reverse was selected was a very bad idea.
Secondly, on newer types, fan blocker doors may well become jammed in the open (deployed) position, and this would not be good for enhanced takeoffs, on short notice.