I hope they can find a way to keep them, it would certainly garner a lot of goodwill. Not like people will stop taking their trains because the melodies are gone, though...
For the digital flipboard on the Keikyu line, it's nice they did it, but I wish they would add a bit more perspective to the flippy parts. Right now it looks like a horizontal scanline just moving down the signs to reveal the next station name underneath.
No, it is impossible to keep them. Computers are not that far advanced yet. The melodies can only be played by pressing a button located at the end of the train.
My line lost its departure melodies in March this year :/
We should get our top frontier models on the task. Perhaps they can devise a motorized finger contraption to push the button without human intervention.
I think I'd be 2% less likely to visit japan without the melodies. I love those things.