RAC - Charts & Price Action, page-321

I must be thick because I still don't get it.

The amount of dilution depends on the amount of capital raised and the price at which it is raised.
It doesn't depend on investor patience,

Take RAC's recent placement for example.
It was made at 60 cents to investors who will be patient.
If it had been made at 70 cents to impatient investors, as you suggested could have been done by RAC having asked Pattersons to market to sophs, there would have been less dilution for the same capital amount raised, so the capital would have been less expensive for RAC.
Most of those impatient sophs would have immediately flipped their shares at 80 cents to more patient investors, but that flipping has no impact on the dilution which had already happened.

I do agree that investors in ASX biotechs are impatient and unskilful.
That leads to mispricings in both directions.