Why would they be able to come up with a solution if costs were to increase now but not in the future?
When there is still an abundance of supply we have the luxury of calmly undergoing a gradual, relatively painless transition. Waiting for decades - or perhaps even centuries - before getting serious about it would greatly increase the degree to which climate change worsens, impose high fuel prices on poorer countries where alternatives would not yet be within reach, create tension between the U.S. and other major consumers of oil, and put us at risk of suffering serious economic shocks - waiting until the last moment gets many people freaked out and behaving in irrational, emotionally-charged ways.
I honestly do not trust consumers to be educated and forwards-looking enough to make responsible choices on a handful of issues like this. If they were perfectly informed, perfectly self-interested, and perfectly choosing preferences in the context of having responsible values this would not be an issue.
It's to buy more time until we get more wind power, more solar power, more CNG vehicles, better batteries and infrastructure for electric cars, and hopefully eventually fusion power.
Which would be great if it were true, but I do not get the impression that either major party in the U.S. is serious about ditching fossil fuels so long as they affect the economies of state and communities to which they feel pressured to pander. All of the congressional candidates in my state this cycle, for example, are in the pro-fossil fuel camp. One of the Democratic contenders took a big risk leading with his opposition to more coal mining and pipelines and got resoundingly crushed in the primaries for it.