At current rates, 5k USD is enough to cover my electricity costs for the next 87 years. Your quoted prices still make them a non-starter in (probably) most of the world.
$0.03 * 11,000kWh/year * 87 years = $28,710.
So either you're vastly underestimating the amount you pay in electricity, or you're using vastly less electricity in which case you obviously wouldn't get a 10kW system.
Before all this our power bills were smack on $100 per month, so I’ve got about a 6.5 year pay off. Electricity here is 13 cents per kWh, but is confirmed to increase 5% per year basically forever. So my pay off is less than that.
Thats ummm extremely cheap.
So saying most people have an 80 year payback period just feels wildly off (depending on the assumptions in the calculation I think that implies less than a penny per kWh generated).
The panels are also a hedge against that uncertainty and provide self reliance
For places not already on the grid, using batteries instead of paying for a new grid connection is close enough to be a question worth asking, though from what I've seen not a definite "yes" or "no" in general.
I highly doubt there is anywhere in the world where you can buy the amount of energy specified by the parent as cheaply as you said. Like i think it would work out to less then a penny per kwh
If you are not accounting for amount of generation than this is an apples and oranges comparison.