The bottom line is that it is not the time yet for this - subsidised small scale to stimulate the development of the technology - yes; large scale plants or "rooftop" programs - I don't think so.
I agree with that, now isn't the time for large scale photovoltaics. Maybe in 30 years when there's no more gas to burn for electricity, we're making do with far less electricity (and paying more for it) than today and if the PV cost per peak watt has come down by half an order of magnitude or so, PV will make a significant contribution of ~10-20%.

However even then other electricity generation techniques may end up being significantly cheaper permanently relegating PV to niche applications.

It looks like we have similar opinions on that. Of course at this point it is quite speculative because of the uncertainties you pointed out.

Nevertheless I support photovaltaics as much as I support nuclear fusion (and maybe even more). And just like with fusion I would object to spend disproportional share of our limited resources for an unproven technology that can turn out to be a dead end.