Does a worn chain really make that much of a difference?

[Sunny Portrush]

you were either very tolerant of issues or that bike was a marvel. Will it take a bow? A pic?
You must have at least changed a brake block?
On the chain thing, on average bikes (not your sainted one) I would replace the chain pretty regularly to avoid trashing the chainrings.

This was 30 years ago, we never had cleaning products in those days

Yes, I did change brakes and punctures but that was it - that bike did thousands of miles, a proper steel thing too

 

[Ming the Merciless]

Blimey Ming, you replaced your chain and doubled your average speed!

Went up by a factor of 8!

 

[SkipdiverJohn]

Back in the days when transmissions were of good quality steel, and chains weren't made as narrow as humanly possible, this stuff just didn't wear out in five minutes even if the bike was neglected and ridden a lot. I wore out the tyres more than once on my first drop bar "racer", and replaced sets of brake blocks, but I never replaced the chain or the rear mech in all that time. The pedals also lasted the whole time I had it, until it got too small for me so I sold it and bought a bigger size.
Modern bikes are nowhere near as durable as vintage steel bikes. Low end moderns are made of low grade steel where they shouldn't be, and high end ones are flimsy and under-engineered to save weight. if you go out and get hold of a five speed "racer" from the 60's or 70's, or an old 3-speed roadster, with a steel cottered crankset, that transmission will almost certainly still be the original one fitted at the factory. Even low end gas pipe bikes were durable machines back then.