Two questions you should ask....
Does the cost outweigh the benefit
Is it a want or a need?
Figures for my own circumstances are as follows.
Location is Tasmania. Installation in my roof at 22 degree pitch facing 20 degrees West of true North.
Energy rate on general Light & Power tariff is 25.132c / kWh. Same rate applies to import and export, and is a constant rate 24/7/365. There is no difference in the rate for solar versus non-solar households. (Note: space heating, air-conditioning and hot water are separately metered at a lower rate and will not be affected in any way by the installation of solar).
For a first installation which qualifies for the rebates, the annual return to the householder is 22.5% p.a. based on installed cost of $2050 and production of 1840 kWh p.a. from a 1.5 kW system.
Based on forecast electricity prices, this return rises to 28.1% p.a. two years from now with ongoing increases after that. Note that the extent of forecast increases in Tasmania, 25%, are at the bottom end of the scale nationally - it's expected to be even worse in the other states.
Now, go and find me another investment which returns 22.5%, indexed to the price of electricity and with no tax payable.
From the perspective of the householder, solar is absolutely a good investment. It sure beats putting your money into property or a generic share fund. Obviously there are subsidies involved, but the entire economy is riddled with subsidies and I don't blame the average person for seeing an opportunity to save themselves some money by grabbing what's on offer.
As for why electricity prices are rising, it's a complex issue but I'll give you the number one cause straight up.
The National Electricity Market (NEM) and the "micro-economic reforms" of the 1990's have always been well understood by those with knowledge of the industry to lower the technical operating efficiency of existing power stations, increase the cost of transmission and distribution through loss of integration and ramp up costs as a result.
Ask the economists and politicians why they thought it was a good idea to focus on one part of the industry which only ever accounted for 2 - 20% of household retail prices anyway (depending on what state you are in - lowest in Vic and Tas, highest in WA, SA, NT) whilst blowing out the remaining 80 - 98% of costs as a direct result.
You'd have to speak to an economist or politician to answer that one - but it was known at least as far back as 1993 that lower efficiency would be the outcome and this was never kept secret (indeed the reverse is somewhat true).
The old state utilities had their faults, but they sure didn't employ an army of people sitting in offices trying to work out how to force the use of
less efficient means of production so as to ramp up the price. This, I can assure you, is exactly what goes on these days...