macs generally dont need dvds to work with peripherals. and if they do, you can usually download the software from the peripheral maker's website. so it's really a non-issue, and a slight inconvenience at best.
but chances are even if it comes with a dvd, you wont need it for mac. like printers for example - all my printers come with a mac dvd but i never need it because mac just works with them automatically.
I'm only guessing but it is no coincidence that Lion and Mountain Lion can only be bought be download from App Store. Apple may well only want to sell this way in the future, via the App Store. So no need for DVD facilities.