In some cases the fixing nuts and bolts have come loose.

My next door neighbour's TV antenna was hanging off the chimney for years
with perfectly satisfactory reception.

I've never had an outside TV antenna. A length of wire hanging out of the
socket on the back of the receiver always worked for me until the cotton
curtains were replaced by aluminium venetian blinds.

A polarisation error of 45 degrees of a dipole results in only 3 dB smaller
signal. This is not noticed in areas of good signal strength where most
people live. Polarisation doesn't seem to bother mobile phone users very
much either.

It is necessary only that interfering signals and echos, if there are any,
are minimised. And that depends more on the direction from which waves are
received.
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Reg.