Confusion about when it's my navigation, and when it's ATC

Mxsmanic wrote:

Since you cannot test the real aircraft that high, you have no
way of knowing whether the simulation is accurate or not.

Brilliant. How do we get there in the first place? What
limiters do you suppose in a normally-aspirated,
piston-engine A/C would prevent us? Barring extraordinary
ridge lift in winter-cold air, and maybe that would be
insufficient, how do we get to FL 300 like I've done in MSFS
in a 172? Possible only with slew. And what's that silly
MSFS phugoid thing all about in this rarefied air? It's
program code; not reality.

F--