I’m surprised no one has posted this reason yet:
It is much cheaper NOT to. Saves on both labor costs and materials costs.
Even Fetterman should be able to figure that out.
Guys’ sleepwear, even inexpensive, with an elastic band @ the waist, usually have fly’s though. This stuff (even in China) is mostly automated - the cost can’t be all that much, but I suppose a few pennies is a factor...
But all this misses my point - why don’t the search engines turn this up? When they do have plenty of content on inane subjects that pop up seemingly at random such as: “Is Paul McCartney really a jerk?” (Apparently NOT, by most accounts.)
;-)