Geoff - we have already built more than 100 nukes in the United States. We know what kind of physical resources and labor are required. The big challenge for that construction process is the external impacts of legal and political challenges. Of course, those sometimes affect oil projects as well, but some extraction, transportation and refining processes simply too freaking hard from a physical resources point of view.
I think you are selling fission short with regard to its fungibility with other heat sources. From many perspectives, heavy metal fission is a more capable heat source than hydrocarbon combustion.
Fission is well proven as a transportation heat source on board some very demanding platforms (subs, carriers, ice breakers, Arctic ore carriers). It is a great source of district heat (as is done in Switzerland) and as the electricity supply for heat pumps. It can supply transportation needs via electricity supply for rail roads and subways, and it competes with many grades of oil as the heat for industrial processes.
In the US electricity market OIL might be a niche supplier - unless you are in Hawaii, Alaska, Puerto Rico, Guam, or on Long Island - but natural gas certainly is no niche supplier. It has a 20% market share and the consumption of gas in electrical power plants represents about 1/3 of the gas market (about 7 TCF per year compared to a total market of 20 TCF). Around the globe, natural gas and LNG compete head on with nuclear in the electricity market.
I am really confused with your comment about storage and portability. A guy with a backpack can carry as much energy value of uranium as a supertanker. When compared to the storage limitations on natural gas . . .
A 1000 MWe nuclear plant only needs 20 tons of manufactured fuel per year. You can put that on a single over-the-road truck. A nuclear plant operator can store as much fuel on site as desired; it does not take up much space and does not cost very much compared to the value of the energy produced. (A ton of commercial nuclear fuel costs less than $2 million and can produce 15,000 MW-days of electricity - that's a fuel cost of about $5 per megawatt-hour.)
WRT portability - the restrictions there are legal, not physical. NASA has developed trashcan sized reactors. The US Army built tiny little plants for Greenland, Alaska, Antarctica, and Wyoming.
Oil will remain a very useful commodity. I just know enough about the way that supply and demand works in that market to believe that the price will fall low enough to make it not worth the effort to try to recover some of the very remote and difficult oil. I see demand falling considerably below 80 million barrels per day as customers are offered cleaner, cheaper, more reliable sources for many needs that are currently supplied by oil and natural gas. What do you think the price would be if the world oil market dropped to 60 or 40 million barrels of oil per day?
Sorry if that disrupts some existing business models. The writing has been on the wall for 60 years and the people who run oil/gas (most majors are at least 50/50 in each product) companies are smart enough to read.