Hiking, which eats even quality shoes because sliding down a mountain side tends to pull apart rubber. These need to be able to go through creeks, slide down mountains, and still be comfortable to walk up to 20 miles in.

Martial arts, because mat shoes need to be soft enough to not injure a sparring partner, but still get used aggressively for hours every week.

Semi-formal shoes for work and going out.

Casual shoes for mowing the lawn in or other house work.

Flat-footed trainers for the gym, kept clean of any oil or other hazards (which is why they can't overlap with the lawn mowing shoes).

A pair of decent, well shined shoes for truly formal occasions (weddings, funerals).

Water shoes, for swimming in water holes and going tubing down the local river.

Note here that I don't run, which apparently truly eats shoes, and all of my shoes are high quality except my lawn mowing/house work shoes, because they're exposed to all sorts of crap like paint. These are just the shoes I've bought this year - my safety boots are still in decent condition, and it's likely my dress shoes will be last many more years.

This would depend heavily on weather. Not everybody is living in California. There are places when you need five different pairs of footwear just to survive a year. Some might last, some won't. Throw someting in to wear indoors.

1. It is not a matter of "need", rather a matter of comfort and practicality. (I leave in mountains).

2. I do have half a dozen different types of shoes (something like 1 or 2 pairs of army boots, 1 for cycling, 1 for MB-hiking-gardening, 1 for gardening, 1 pair of tennis shoes to wander in and around the house, and probably 1 old worn spare one I forget about). It doesn't mean I buy them all every year. I haven't bought any in 2017 or 2018. The army boots are 5 to 10 years old, same for the hiking shoes I use for mountain-biking (4 years old?) and gardening (15 years old?), since I cannot really hike any more. The tennis/cycling shoes are dying but they were already dying last year and in fact they are still good enough :-) So I probably buy only 1, perhaps 2 pairs, in an average year.

It is only a matter of comfort, and not survival, if you own a car and drive it around exclusively. If you own a car, well, impact(car) > impact(any number of pairs of shoes).

I'm still skeptical. I have one pair of shoes for day to day usage, one nice pair for dress up, on pair of snow boots, and one pair of slippers. Each has lasted me many years, and I live in Wisconsin which isn't known for having anything like California's weather.

Climbing shoes on the other hand I need to have resoled every 6 months or so.

Certain types of athletic shoes wear out long before they start to fall apart. Some people might replace their shoes to avoid injury or for performance reasons.

It also depends on activity levels.