That statement to me shows you even have difficulty conceptualizing what a non-gamified model even look like! (.e.g "sufficiently-evil enemies to kill").

Simulation has much more elements of tedium (no "pacing"), just like real life.

Or the learning curve is not constructed just so to be the perfect on-ramp, just like real life. The learning curve is simply what nature/environment demands.

e.g. "Enemies" are not "sufficiently evil", or even presented to you at proper game-enjoyment level times/pacing.

It is why simulations are not really "games", they are not "fun" (but the can be, but that isn't the "point"), but my point was that something draws people to them, and they engage with them. It's interesting to think about why.

Flight simulators do not have the same moral quandary, so we don't have to worry about it there: we can ask the question "is flying fun"... and you seem to have ignored my premise which is that the answer is apparently "yes": people who own planes report that flying is fun.

However, most people can't fly, as it requires you to have a ton of disposable income to own the plane and contract the hanger and pay for the fuel. The people I know who own planes hardly ever get to fly them, and when you do get to fly you are often almost "forced to" in order to keep your training up to date.

Regardless, it is worth noting that you have now slipped into the territory of having defined a simulation as something inherently not fun, so we should ask if a flight simulator even qualifies for your circular definition, and it turns out it doesn't :/.

So, the reason why a true combat simulator (with the caveat that the enemy is "sufficiently evil") would be "not fun" is that most of combat is "hurry up and wait", maintaining your equipment, and doing training exercises. What makes a first person shooter fun is that you get to do only the parts that are thrilling, challenging, and engaging: even your gun is maintained by other people.

A flight simulator is thereby not really a simulator, as if it were 99% of your time would be spent making money to buy fuel. You would only get to fly a couple times a month at most, and your plane would even be in the shop a lot. You would be managing your flight certification credits more than your air traffic control, and you would have a pretty limited set of destinations.

In Flight Simulator, you can fly any plane, from anywhere to anywhere, the plane always works (unless you ask for it to not work), you get to decide how bad (aka, "exciting") the weather is, and the fuel is effectively free. You get to spend all of your time doing the parts that are thrilling, challenging, and engaging.

The closest you can get to this experience in the real world is flying commercially, whether for a large airline (in which case you do get to fly large aircraft--which is both interesting and boring--but mostly in good weather on someone else's schedule) or you start your own small business flying people around (in which case we would expect a bunch of sales and accounting hours).