Unfortuantely, it is all down to cost.
At the moment, the use of renewable energy is more costly than conventional methods, firstly because conventional power production sites are already in place, but new renewable ones would need to be built from scractch - therefore there is an investment cost that needs to be paid either by governments or by private individuals.
Governments are unlikely to fund them, because to do this they would need to raise revenue from tax payers who would (in the main) be unhappy about it, and governments don't like doing things that they think will make large numbers of people unhappy because they want to stay in power, not be voted out. Private investors are unlikely to fund them because they generally do not make a sufficiently high return on the investment.
It is also true that getting power purely from renewable means tends to be somewhat more costly on a per unit basis than conventional methods.
So the only way this would work is for the majority of people to start saying "I know this will cost me more, both in taxes to build new installations, and in energy costs, but I am prepared to pay anyway". That is extremely unlikely to happen, because whilst many people are concerned about climate change and the fact that fossil fuels will not be around forever, the vast majority are absolutely unwilling to pay anymore towards solving the problem. Most believe it is someone else's job to pay (i.e. the power generation companies, or 'richer people') - the general view is that power generation companies make too much profit (although strangely enough we seem to like the idea that power generation companies employee large numbers of people, and by the large amount of profit they do make, provide a sizeable contribution to the government's tax revenues).
Most people are content to be led around by the nose by the media and the ill informed, so its very little surprise that they fail to understand much, including this subject.