This is the problem with comic books when they try and mix real time with comic time.
If they say Barry has been gone that long, then as G-Man said, that would make Superman etc, be in their 50s (40s at the very least).
It would also make it seem like Barry only operated for a year or so before dying.
And as thedoctor pointed out, the last months of Barrys life were spent living in the 30th century, where I am quiet sure he would have come into contact with technology vastly superior to the modern day.
Maybe what they are gonna do is another Hawkman balls up, where they essentially wipe out a whole bunch of continuity on a whim, then realise how much it actually fucks up the rest of the DCU and have to rectify it with some bullshit new story!
