Atari's greatest hit the 2600 was never equalled, but they never managed to create a successor for the product. Maybe because they fired Nolan Bushnell, or maybe because of the leadership of Warner. so I don't think anyone out-ataried the atari - they just stagnated and died.
And the Newton was never a success, so there wasn't really much to out-newton. It was too far ahead of it's time, and the technology wasn't quite there yet.
1. Your observations about Atari and Newton highlight one of the problems with your initial argument- it's not generally a safe bet to assume an early category-creating product will continue to innovate and develop to stay at the front of the pack.
2. Whether RIM creates a broadly superior product is beside the point. A new market has opened up, and they expect it should be profitable if they can capture just a small share of that market.
Apple has shown a commitment to develop their successful product lines; but as the size of the market grows there will be plenty of room for profitable competitors even if Apple is wildly successful.
And the Newton was never a success, so there wasn't really much to out-newton. It was too far ahead of it's time, and the technology wasn't quite there yet.