Then maybe they should charge a subscription fee for them if it's otherwise uneconomical to keep providing them.

iOS updates used to be paid in the past (due to Sarbanes-Oxley in the US)!

Here in the UK, updates for the first iPhone were free, but (in the beginning) the major updates for the iPod touch used to be paid for.

(Unless you downloaded the update file from Apple's CDN directly and manually updated your iPod Touch via iTunes, not that I ever did that as that would be very naughty ;-))

They're included in the initial purchase price and the cut apple takes from customers' appstore purchases. Nothing is free.