I meet lots of people who feel exactly this way. For many people, shifting is a mystery, and a frightening one at that. That's why we have the automatic transmissions in most of today's automobiles.

Answer, is probably none but how many bikes do I find each year with one, or both, derailleurs miserably out of tune? The answer is hundreds and I am not exaggerating. Through Bicycles for Humanity, I get to inspect (with the help of many other volunteers) about a thousand bikes each year. Most have transmissions that are not in good working order. And the people who donated the bicycles would have had to deal with the poorly functioning transmissions when they owned the bike.

Dealing with derailleur issues is not intimidating for most of us who frequent this forum. But for someone who does not understand the rear derailleur, changing a rear tire can become a nightmare.

The "would be but knows very little mechanic", stuck at the side of the road, will not even know to shift the rear derailleur to the smallest cog before, removing the rear wheel. When it is time to install the wheel, they are often times stumped until shown why it is so difficult to get the axles to go into the drops. I show them how to ensure the chain is on the appropriate cog and away they go. Honestly, I see it all the time. Simple for us but a complete mystery to the untrained.

So, that one fact alone makes it easier, or simpler if you wish, to change the tire on a Single Speed.