All of this is true, but it ignores the fact that the two major parties pretty much agree on many important issues (such as government monitoring of internet traffic).
Also the fact that (especially with a hung parliament which we've had for years) independents get an outsized voice is a bit of a two-edged sword. It's far more luck than anything else that determines who's in that vote-tipping seat and sometimes they demand all sorts of special-interest stuff in order to let things through.
For the lower house, we've had many years of the balance of power in the hands of a small number of independents who get an outsized voice.
Yes, if you live in an non-swing electorate, that is strongly held by the incumbent, then you could argue that your vote doesn't matter, but only because there are more people voting for something else. Isn't that how things are meant to work?