I think there are two main reasons whu investors would shy away from renewables in Australia:
1) Firstly there are no large well-known actors, so there is uncertainty around renewable energy companies are going to "win".
2) Secondly, Australia currently has a government that is hostile towards renewables. It could at any time introduce legislation that would make renewables economically untennable.
These are both true, furthermore a lot of the bigger players became big as a result of the initial round of solar rebate schemes - where a lot of low quality solar installations were put up. Now a lot of these companies are doing much larger jobs without the necessary skillsets. There's a bit of a minefield of shoddy installers still out there - look at the Crap Solar Facebook page for an insider look (there are some horrific installations).
Despite all this, I've seen a huge amount of interest in investors wanting large scale commercial and utility scale solar projects. From what I know, solar engineering consultancies are turning jobs away due to the demand being so great.
Even with the evilest scheme, it seems unlikely to come up with something harming the rentability of renewables, or of solar in particular. It's basically free electricity from sun, which is plenty in Australian deserts. You pay only the installation, which price is determined by the tech market.
1) Firstly there are no large well-known actors, so there is uncertainty around renewable energy companies are going to "win".
2) Secondly, Australia currently has a government that is hostile towards renewables. It could at any time introduce legislation that would make renewables economically untennable.