I had an an old boss who did not grasp this principle and was convinced he would get rich writing a similar tool because all the other's where rubbish and not what he needed.
He even talked to several other small business owners who felt the same and thus was convinced that he would sell to them fine. He didn't realise that when he showed them the actual tool they'd want something different ...
Anyway, I left that company many years ago :-)
As well as not being built for you, it was also not built by you. I believe NIH syndrome is responsible for the glut of half-finished programmer tools that litter the SaaS market.
That's not to say that there is not room for another bug tracker, nor that there is anything wrong with a touch of NIH syndrome here and there.
But I think that the problem is not that "Some are great but expensive, others haven't changed in years, most are too complex and are re-hashes of the same product." The problem is that they have not been built for you.
This is why there are so many bug tracking, to-do list and project management solutions. Savvy people aren't satisfied with what they found because it does not fit 100% with their ideal solution so they want a custom one. So they say: "Hey look what I've build! It's so much better than the others". It's true for you and maybe for some other people but it's not true in general. It's just that everyone wants a custom bugtracking, to-do list or project management app.