No, it's not cheap glass, hell, it has lasted since '54.

Light is refracted through glass, as through water, so your view is
skewered. I'm almost certain your glass is 1/4". 1/8" glass, that
large, would have been broken, by now (60 yrs), from some form of wind
pressure... accidental slamming of a door, causing a concussion type
pressure enough to break a 1/8" pane that large.

I'm at a loss for a remedy to remove the panes/sashes. About the only
other thing I could suggest, without more detaled pics (of what?), is
to spray the edges with lithium spray lubricant and see if that
helps. Spray just enough to dampen, not to run or drip so much. If
that doesn't help, at least your lithium won't be wasted..... spray
some on a cloth and wipe the remaining sash edges and jams in your
home, making for smoother opening and closing of the windows (I'm
assuming up-down slide type). Lithium isn't oily, per se, and is
great for lubricating sticking sashes and the like. Spray a cloth and
wipe. Don't spray the sashes and jams, then wipe. Doesn't take much
for good lubrication.

Lithium spray lubricant should be available at any good hardware
store. I've never look for it at Lowes, Home Depot or the like, but
they may have it.

Sonny