Should kid blu-ray movies have standard dvd also?

[zipbags]

I have stopped buying regular dvd's. Except for kids movies and tv shows. The reason I still buy kids movies is that a lot of the times my kids watch them in portable players or in there playroom. I would love them on blu. But, like I said. They want to watch them elsewhere and until blu is cheap enough for extra players or a portable. Its not going to happen. I know hd-dvd had some movies with both hd and standard. But, does anyone think that on kid releases they should include standard dvd version on a blu disc? For example "Enchanted", "Mr.Magoriums", etc. Again, this is for kid movies.