• Yes, you may need that many gears.
If I had a dime for every time I heard “Why does anyone need that many gears?”
Bikes today aren’t equipped with as many as 30 gears for frivolous reasons. An automobile with 200+ horsepower is often equipped with a 5 or 6 speed transmission. By comparison, an elite athlete may only put out ¼ horsepower. Wouldn’t it be logical that the sub ¼ horsepower engine (you) on your bike be equipped with a proper transmission to make up for the lack of power?
A bicyclist riding over varying terrain or over great distances will be able to get the most from their limited power by riding efficient. The more gears, the more the rider will be able to keep their legs turning at an efficient pace, regardless of terrain or speed. The number of gears you need is dependent on your planned riding style.
I have a 20 speed road bike and a 24 speed mountain bike, but I also get great joy from single speed or three speed bikes. The key is picking the right gear for your type of riding.
• "Who would spend $500 on a bicycle?"
When I worked at a bike ship in college, I once sold a Schwinn AirDyne stationary bike to women looking to get into shape. It was a good purchase and wasn't cheap. As I recall, she didn't get the cheapest model, she dropped about $600 on it. No complaint from me, she bought a bullet-proof stationary bike. On her way out the door, she looked at the price a a mountain bike and exclaimed: "Who would pay $500 for a bicycle?!!!" The funny thing was, she dropped 600 bucks on a bike that didn't even go anywhere.
I didn't begrudge her her $600 stationary and I don't begrudge the person who drops $2,300 on a custom steel frameset. Its all good, its all in what we enjoy.
• I want a wide, comfortable saddle.
You do if your bike is made for it.
You sure about that?...