You pretty much covered that accurately. I also install commercially occasionally and even with the best prices on materials and my cost to install, I can not come close to a decent ROI in Canada. Is far worse if I install batteries to make it a non grid tie system and still work in the event of a power failure. Also the specifications and published returns most companies will give you are out to lunch in real environment. You will never achieve the full output of the panels and you will on average only produce power around half the time they predict.

The only place I could justify a system was in Mexico where my power was around 40c US a KWh, we have sun 300 days of the year and grid feed pays us the full 40c rate. I am still looking at a 7 year return and that is at their cheap labor to install on a 5kw system grid tied. (BTW grid tied in my city in Mexico is causing havec on the grid for complex reasons I won’t go into here.)

I look at it this way. Batteries and their respective systems are a no go from the start. Just too expensive and limited lifespan. This a grid tie system if you really want to tie in. But that will disconnect in the event of power failure. If dependable is the ultimate requirement, just install a power failure generator. For the few times a year it operates, will be far cheaper, can actually power the entire house typically and it can power indefinitely. An expensive battery system might get you half a day if you spent a great deal on batteries while being power wise at the same time.