Why doesn't Apple subsidize the cost of the POS devices that are compatible with Apple Pay? If the big hurdle for businesses, big and small, is the cost of upgrading their POS, then perhaps a company with $200B in cash sitting around could help pay for that. Average POS device is $2000 (1), and there are 10 million POS devices (2) in the US. If Apple covers 50% of everyone's upgrade, that's $10B. About 3 months of profit for Apple.
I believe the reason is because all those paypoints have to be upgraded to handle Chiped cards by the beginning of next year. Why lose 3 month's profit when in 6 month's time, the same result will happen.
At least, I don't think there are many modern paypoints that don't allow for NFC payment.
The POS does not need to be compatible. The card reader alone does. The relatively high end Verifone VX 680 devices (which are the most popular in the UK from what I can tell), cost about $300 each. Really not that much.
Your cost per station is wildly undervaluing things, since you are not taking into account shipping, installation, training, verification, auditing, disaster recovery planning, etc, etc.
Forgetting the exact cost, Apple has enough cash to give retailers an incentive and may have already done that with those that are already onboard. Note I said "incentive" not "paid for everything". This wouldn't be something that they would necessarily disclose either, for obvious reasons.
1 - http://smallbusiness.costhelper.com/point-of-sale.html 2 - http://www.gaoresearch.com/POS/pos.php