But they are just making computers (including a pretty large set of software to run on them). Granted, they come in different sizes (smartphone, tablet, laptop), but especially with the very recent switch to ARM based SoCs, at least the mobile products are very similar under the hood. As you say, leveraging existing competencies. Which is what I was arguing: What indicates that Canon or Nikon have such competencies?With your line of thinking, Apple would still be just doing computers. Instead, they diversified by leveraging their existing competencies to enter new markets.
Canon especially has greatly diversified into medical, security and machine vision applications for industrial use. So, more B2B oriented and much closer to their existing competencies.
I am not even saying that they couldn't or won't enter the market for drones or do some first party accessories for the cinema line. I was just responding to the notion that it is such a no brainer to do so.
Also as far as anything goes, Apple is not an example that generalizes well. Their tight ecosystem means when they make an accessory like the ear pods or the Mac Pro screen, these products compete under very different market conditions than a Canon gimbal, recorder or drone would.