It's all a bit of a mish-mash at the moment.
DVD was a format for phyiscal distribution of media. But DVDs quality had reached its limits and people started wanting the instant acess of the internet and higher quality of HD.
There is no doubt that's where things are heading, but given all the competition and lack of dominant standards, it does seem like the convenience and ease of DVD (thanks in part to iDVD) has been 'end-of-life'd a bit prematurely.
Apple's approach for a while was Front Row, but then that got killed off too, presumably deciding Apple TV was a better platform it.
If you want to stick with DVDs (or Blu Ray) then there are alternatives to iDVD that are still actively supported, perhaps a question the iDVD forum will help.
But most of the focus now seems on media streaming Apps, for both your local network and internet (receive and broadcast). The trouble is it's still in it's infancy and standards are basic (do a search on DLNA or check out this for a brief introduction: http://www.techradar.com/news/digital-home/home-networking/dlna-what-it-is-and-w hat-you-need-to-know-1079015 ).
The problem is, while DVD was universal, streaming frameworks are not and so currently it's a lot easier to share Apple created content with your Apple owning friends and family than it is with people in a different ecosystem. Before you just had to know if your friends family had a DVD player, now you need to understand their media streaming setup!!
Dispite Apple not participating in DLNA (presumably because it's still much too technical for the layperson and Apple has competing technologies for Apple devices) there are Apps and devices that bridge the gap.
The question is do you want to stick with DVD for now, or make the (inevitable) switch to electronic/streaming distribution. If the latter it's not currently a simple switch from one approach to the other, it's about starting a whole new learning curve.
Andy