Tablets are just a computer with onscreen keyboard and touchscreen pointing deveice. Original, but not totally original, and not my point.
Releasing a totally new computer platform it very expensive, and difficult and likely to fail. Natami and the others have the deck stacked against them. Not to say that they will fail, but if the a5000, access stuff, boXer and others are any indication...
And the most popular tablet (that most might argue kickstarted the market) was the iPad which is a new computer platform running an OS not seen before 2007. The other tablets, Android, came about even later. Was it expensive to develop, probably, and both of these are backed by companies with pretty big bankrolls. But to say nope, no new platforms can succeed is flying in the face of evidence to the contrary.
Dreams and drive do only get you so far. But thus far tablets are protected from Microsoft because of them being asleep at the wheel again which has allowed them to succeed. Amiga wont succeed and Commodore USA wont either unless they can find a place where MS and Windows isnt.