Perhaps, but maybe not.
If anyone wants to pick holes in the following, be my guest. However, the broad numbers aren't that far off:
Cost (ex profit) for a 4 kW system right now, including all bit s and bobs and installation: £8,000
So cost/watt = £2
Expected life 25 years, I year has about 8,000 hours, and bright sunlight for about 1,000 of them.
So expected lifetime generation from 1 watt (peak) is about 25,000 watt-hours, or 25 kW hours.
So approximate cost per kW-Hr is about 8 pence per unit which is not ridiculously high.
This doesn't include the cost of borrowing capital, or the cost of the distribution network. Add in the former if you like, but building society returns are less than inflation, whereas electricity costs aren't. The network costs are interesting, because the nature of domestic 4 kW systems is that much of the power will be used by the owner's property, and much of what isn't is likely to be used nearby, which actually REDUCES demands on the distribution network, unlike concentrated wind farms for instance, which increase demands on the network strongly.