Hi Desu,
Ultimately, those products do not require any oil for their construction. There are obvious substitutes for every usage of fossil fuels. Those substitutes have already been developed, and no further technological development is required.
Fossil fuels are not some unique irreplaceable substance. They are ordinary chemicals. They have obvious substitutes, such as electrified transportation and renewable power. Even for the very few usages which really require a chemical combustible fuel (such as air travel), there are many obvious ways of manufacturing such fuels. For example, there are: anhydrous ammonia, dimethyl ether, alcohol fuels such as methanol, biofuels, and many, many others. It's also possible to use metal fuels, such as aluminum, magnesium, and others. It's also possible to manufacture natural gas and oil using renewable energy, using the Sabatier process or the Fischer Tropsch process. There are also many other alternatives being investigated and developed now. As a start, you can find more information about this here:
http://en.wikipedia.org/wiki/Alternative_fuelFossil fuels are used because they're the CHEAPEST way of accomplishing certain things right now. That's the only reason. Fossil fuels are modestly cheaper than alternatives, that's all.
Oil will deplete gradually over more than a century. That is VASTLY more time than the economy requires to transition to alternatives. The economy ROUTINELY and AUTOMATICALLY transitions to alternatives as they become cheaper. This is an EASY PROBLEM for the economy to manage. This is something which the economy does all the time. Some things may become more expensive, but there is no imminent end of civilization because of peak oil.
-Tom S