well, im just talking from my experience...

I had leathers underneath with waterproof overalls, they were a one piece suit, kind of a rubbery inside....actually one set I bought from Lidl and I still have it and works perfectly fine.

the boots cost £20 off ebay and were waterproof, if needed, stick your feet in carrier bags and then put boots on
the helmet was a Caberg that cost £120 new

not saying that everyone has to ride when its raining, just saying there's ways around it.
price of kit to ride in the wet is not a good enough reason to not ride in the wet.

and I wasnt doing 5miles to work either, I was commuting 30 miles each way and weekends from Newbury to Gatwick and bike rallies all over the place...