It's not an unreasonable expectation. Apple might not 'owe' you anything - but at this stage the OP hasn't made the purchase - they are trying to negotiate the purchase. Apple have announced they are updating software soon, OP could wait and buy later, or buy now. Apple would prefer buy now, so it's an exchange, OP agrees not to hold off on his purchase, Apple agrees to give him free software (the marginal cost of which, by the way, is essentially nil).
Or should we not try to negotiate with the almighty Apple gods?