Why does Europe have LHD cars?

Why does Britain have RHD cars and majority of Europe have LHD cars?
Back in the medieval times the majority of people on horseback carried a weapon of their choice a sword, flail, mace, lance etc. The vast majority of the population is right handed; therefore in order to attack or defend one’s self it was necessary to ride on the left side of the trail to be able to use your right hand on said weapon.
France changed this practice of left hand side traffic. This was part of its sweeping social rethink. The change was deployed all over continental Europe by Napoleon. The reason being rather selfish, Napoleon was left handed therefore he made his armies march on the right just so he could keep his sword arm between him and his enemy.
Obviously times have now moved on. But Britain kept the same side to direct traffic. Most countries in Europe do not drive on the left. It's pretty much only the UK. If you look at history, the majorities of the countries that drive on the left now were prior British colonies or influenced by the British. With the exception of America, drive-on-the-right policy was adopted by the USA, which was anxious to remove all remaining links with its British colonial past
So therefore if you have a second home in Europe or travel abroad often, it is beneficial to have a LHD Car.