Marco Arment has a smart take on why the first-generation iPad and iOS 6 don’t mix:
The iPad 1, despite its many great qualities, had a noticeable shortcoming: it only had 256 MB of RAM. This was most apparent in Safari, which could rarely keep background pages in memory and needed to reload them frequently. Reviewers and owners noticed this from day one, and we wondered why Apple didn’t include more RAM.
But when the iPad 1 was released with iOS 3.2 in early 2010, iOS was very different and needed far less RAM. There was no iCloud. No Notification Center or Game Center. No Personal Hotspot, iTunes Match, AirPlay, iMessage, or over-the-air updates. No Newsstand background downloads. And, critically, no multitasking, so no need to keep Skype or Pandora running in the background while playing Fieldrunners or reading Instapaper in the foreground. With the exception of Safari page-reloading, the limited RAM was rarely noticeable.
The hardware market was very different, too. The iPad 1 was the first modern “tablet”, and as we saw (eventually) from its competitors, its $499 price point and excellent battery life were difficult to achieve in 2010 (and even in 2011). More RAM would have added to the component costs and decreased the battery life, potentially making it less appealing and jeopardizing its success, so Apple chose to keep it at only 256 MB.
When iOS 6 was introduced at WWDC this past June, I was surprised it wasn’t optimized for the original iPad. After all, I thought, if Apple could get iOS 6 to run on the 3GS -- albeit, as Marco notes, “barely” -- then surely they could get it to run on the iPad. But they didn’t, and it was for the best. It probably would've sucked.
Myself, I’m keeping my 3G-capable iPad 1 running iOS 5.x (can’t remember the point number) as a momento. It sits in its original packaging, just as my original iPhone does. I’ll be thankful for this ten years from now.