We already know that it takes more energy to, for example, split hydrogen from water than we get out of the hydrogen when we use it as fuel.
You're talking about current technology.
Based on that argument, we should still be using 286 computers with floppy or 10 meg hard drives connecting to the internet on 1200 Baud modems.
No I'm not being sarcastic, I'm simply arguing that things change. What's current today won't be current tomorrow and if we never explore and test and try we'll be saddled with oil until we go into the dustbin of history.
There ARE ways of getting hydrogen cheaper.
We just haven't discovered them yet.