You're cherry picking your locations and months and even then the numbers you post do not fully support your assertions. (Seattle's solar insolation is less than half of yours).
You're the one who stated that your location was colder than any place in the US which is not true - even if you exclude Alaska. Just for example, from the website you link, Angle Inlet, Minnesota is colder. (Dec -14 C, Jan -18.1 C, Feb -14.5 C).
You're the one who said almost all states have better solar resource than you. Depending on what you mean by "almost all" that is also not true.
My only point is that you live in a cold but relatively sunny location in a small, very well insulated home and therefore your attempt to provide for all your energy needs with solar PV is not going to be replicable for many people living off grid in the USA. Yes, or course for many others it will. You're just overselling your assertion is all.
As I've said, I am a big fan of solar PV and it has become a very cost effective energy source - even the most cost effective in some locations. It's not the complete energy solution for everyone (or maybe even most) who lives off grid though.
I did not try to cherry pick a location just took the largest known city in the state you mentioned.
I see that the particular town with a population of 60 people according to google has slightly lower temperatures than my location (not significant) and will require 2 to 3% more energy to heat than at my location.
If you look on the map where that small town is located is basically in Canada
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and it also has lower solar resources but I can call this cherry picking
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I guess most people living offgrid have enough land for a large ground mount PV array. All other energy sources will be way more expensive when you take the entire system in to account.
If you live in a house that already has a natural gas connection and the natural gas furnace then there will be no gain to go with solar PV.
But If you have an offgrid house and you use propane, heating oil or wood/pellets then I will say is extremely likely that PV will be significantly more cost effective especially in cold locations where heating season is a big part of the year.
And this is just the benefit for heating used stand alone but when electricity is also needed the combination of heating and electricity brings even more advantages since it reduces the battery size needed for electricity storage by at least half if not more and makes the offgrid electricity competitive with grid if not better.
The 10kW PV array as mentioned before will produce 14.7MWh in a year at my location and from that I will use around 4000 to 5000kWh for heating depending on winter and in my case just around 1000 to 1200kWh electricity (maybe that will increase in the future but is not relevant there is plenty of excess).
Total cost of the parts including the battery SBMS and inverter that I already have will be around $15k
Assuming a 25 years amortization period where another 1000 to $2000 battery may be needed in the future and a $400 inverter say $17k for 25 years
$17k / 25 years = $680/year = $56.6/month
The PV array that is the main cost of the system will continue to work probably for much more than 25 years so cost amortization will be even lower.
Selecting any other heating option like wood or propane will make the electricity part much more expensive close to 2x the cost mostly because of the higher battery capacity needed.
So while you can split that $57/month in say about $40/month for heating and $17 for electricity the electricity will get to around 30 to $35/month without the oversized PV array used for heating and with the large capacity battery so then your separate heating solution will need to be just $22/month about $264/year in order to be equal with PV heating.
Hope you get the idea related to benefit of combining heating and electricity.
I just do not see any way for any other energy source to compete with PV and PV and Lithium battery prices will only go down while other energy sources will probably stay the same or even go up in price.
And yes there is that disadvantage that you need to pay in advance for all that energy by purchasing the PV panels.
You are right. Wind is rarely the answer as a sole energy source. But there are places where for all practical purposes the wind blows all the time. Much more than even windy places like Regina. Not pleasant places to live at all and generally cloudy also, but if you have to live there wind might work out.
Solar has potential in lots of places. But even with solar there are limitations. In my current case I didn't mention the bottom of a valley location, or the poor orientation of the roofs (driven at least partly by local geometry) of the already existing house. Yes, if you are buying land and building a house intended for solar you can select for these factors, but economics works here also. Prices for land best suited for solar in a given area will rise. Often for reasons unrelated to solar. Hilltop locations which have the most access to solar also tend to be prized view lots in urban areas.
Yes there may be a few places where wind is more constant and maybe good to consider. I'm a bit biased here since I always prefer solid state devices and dislike any moving parts.
Is unfortunate that you have bad access to solar but from what you say that seems a as a grid connected house and live in some sort of urban area. There is always the possibility to move to a location with better solar access
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Most house in urban areas are large and not properly insulated (just minimum by local code) so the surface of the PV array needed to provide 100% of the energy will be high and most likely the space for that will not exist (small lots in urban area).
While solar PV is cheapest it will not work in any place because of this limitations mentioned and probably others.
There is no doubt in my mind that solar PV will probably be the dominant energy source in 10 to 15 years and many things will change with this.