To the OP; I can't quite work out what sort of flying you do on the sim, are you flying heavy jets or light aircraft or a combination of both?
Just a note I have been up in several light aircraft - C152, 172, Piper Arrow, oh and a few stalls in the 152 as well. I have handled the controls as well as far as I remeber they were very heavy and sloppy at the same time.
OK on the sim - C172, PA24 (My favourite fast cruiser), Twin Otter, and Dash 8 -300. Wow I sound like a real pilot. The heavy jets I have not in any way mastered yet.
You mention switching the autopilot on; very few light aircraft have an autopilot. I fly a reasonable selection of types and only one of them has an autopilot, and that is more of an unusual attitude generator than an autopilot.... I leave it off unless I want to amuse myself with it's attempts to fly anywhere but where I want to go.
The C172 has an autopilot as well as the PA24. It's of course again classically non-intuitive, switch it on and there are several identical buttons that change between HDG, RDL and the vertical speed automatically captures the current vertical speed you are at.
Ah here it is :
Bendix/King KAP140 Autopilot - FlightGear wiki
Flying light aircraft is a completely different ball game to flying a big jet, apart from the obvious dynamic differences. You should be able to cope with a complete instrument failure in a light aircraft and still be able to land safely. The ASI does give you airspeed but so does the sound of the slipstream, the weird and wonderful noises that different vents and intakes on the aircraft make at certain speeds and how the controls feel. I don't need an altimeter to land VFR, no qualified pilot does, you do it by looking out the window. You fly mostly by feel and the picture out of the window looking right. You get none of this on a flight sim. I'm not knocking flight sims by the way, they are good fun but do they recreate the sensations of flight? Well no, how can they?
I admit flying the sim is completely usuited to 'flying by looking outside'. Maybe VR Glassses are the way to go. Virtual Reality. Might give me vertigo, though.
Edit: Having seen the money, time and effort that some people put into their sim rigs they probably spend more on simming than I do flying. Each to their own though.
It's not out of reach financially then, not for me either, however there is the risk, which will not be discussed here.
Suffice to say, the older you are, the less risk you want to take. I mean would accompany a friend pilot in a single engined plane over snow capped mountains .. did it once, long time ago.