Why mostly manual cars in UK

The only reason modern cars have dual mass flywheels is they can cut costs by using weaker crankshafts and gearboxes. It's cheaper to make a dual mass flywheel than stronger cranks and gearboxes.

If you fit a solid flywheel to most modern cars you will snap the crank!

a lot of modern cars these days Allow you to choose between automatic and manual. I have a Audi with an S-Tronic box which I can leave in “D” or change to “M” which allows me to use the paddles to change gears. Best of both worlds I suppose.

I repeat, my car doesn’t have a dual mass flywheel and it’s not yet three years old.

Any clues to what you drive?

To return to the original question (but why change the habits ... etc) -

Before WW2, most cars had gearboxes that required experience and skill to operate. So, most drivers avoided changing gear, and looked for cars which did not require such skills. Meeting the demand, makers used low compression engines with unexciting valve timing and big flywheels, and these cars were capable of about 5 - 50 mph in top gear. At the time the UK speed limit was 20 mph, so there was no incentive for much progress. As a result, the enthusiast (who had, or tried to have, the needed skills) relied on a specialist market place os what we would now call sports models, if he could afford it.

In the 1930s, fluid flywheels, and then synchromesh, were developed and much of the problem went away. At the same time, the removal of the 20 mph limit and the wider spread of tarmac in the countryside encouraged the use of valve overlap (shock horror), and lots of smaller-car firms turned out 'sports cars' - Wolseley, MG, Singer, Frazer-Nash, Riley, Alfa-Romeo, etc. The divide between 'ordinary motors' with saloon (sedan) bodies, and old-fashioned performance, and 'sports cars' with touring (open) bodies continued the idea that 'proper motoring' required skill, and anything that took away the need for skill was regarded as only for women and old men - and this included easy-changing systems. And such notions tend to stick - you only have to look at Top Gear to be reminded of this.

In other countries away from the UK with its restrictions and aged traditions different rules applied, of course.

I hope this bit of background is helpful.

Cheers, Tim