Due to the rotation of the Earth and unpredictable weather patterns solar energy is not experienced by life forms as a constant source of energy. Solar energy must be stored for use in times when the sun isn't shining. All forms of life have developed mechanisms for doing this. Our industrial society is also capable of doing so. The energy we receive from the sun is on the low power end of the spectrum.
Oil is a very concentrated form of energy.
Sunlight is not. For instance, it is difficult for the sunlight falling on a vehicle to be able to power the vehicle. There are solar car races held every year, but these are very light weight vehicles with only one passenger, more like bicycles. Sunlight can of course be concentrated. When it is, it can be very powerful.