Earlier quoted context omitted.
What about trial versions? Are they supported by the app stores already? Seems like they'd solve the psychological problem.
Conversion on anything trial-like, is going to be very small, and likely worse than even an upfront purchase because you will hit some people who are satiated with a small amount of trial gameplay or people who decide not to buy after playing. Keep in mind that the best premium apps have lifetime revenues in the low tens of millions, and the best F2P are in the billions.
The inverse of this is likely just as true, sales are not made due to there being no free trial so someone just doesn't bother with it at all.