Li Shenron
Legend
If you dont have a trap every 5 ft there's no need to roll. I don't think anyone ever did that. Not that I have experienced anyway.
You don't need to have a trap every 5ft, all that it takes is a bad adventure/DM that places traps in locations so random (e.g. the casual tile on the floor) that they are impossible to guess with reason -> players get frustrated by springing traps randomly -> players declare that they now check every single tile in the floor -> DM has them roll every check separately -> everybody gets bored and think the game (rather than the adventure/DM) sucks -> game desigers step in to save the game and introduce a rule to avoid too many rolls.
It might be very much theorycraft, but at different times it has been a vocal one, and it's been going on for a long time (see Take 10 in 3e).