and the DEM has always been in a native digital format. The whole problem here is that the aerials and conventional maps are not, they're on paper and film and fiche. It takes a lot of time and money to get it digitized and available and USGS was not able to do that for a long time. You could argue that Google's generous offer to digitize the EROS archives contributed to the delays on this.
Keep in mind that when we talk about the EROS archives we're talking about data that goes back to the 1930s and earlier for some product types.
For a long time I got the topo maps from the website of a state government bureau that had conveniently run them through their own large-format scanner and posted the TIFFs - USGS didn't get around to it for years after. It's hard to blame them too much as they had a shoestring budget.
Actually, for amusement value, that state agency appears to have removed the TIFFs from their website and now says that you can order the topo maps by mail for $8 a piece, which is what I used to have to do. I wonder if USGS got mad at them, which is a bit ironic since they don't mention that USGS themselves only recently started offering them online for free. For additional amusement value EarthExplorer, the fairly new service that lets you retrieve aerials online, has a banner up that downloads are intermittently broken and indeed I can't get it to work at the moment.
