Without makeup?... well...
There would still be very attractive people. Some people just have great skin, few flaws, red lips.
The problem is, the demand for these people (in everything, from personal life to business) is very high... much higher than natural supply. So, that leaves the market trying to fill those gaps by other means.
Development of better makeup, airbrushing and post-production type work, surgery, creams and vitamins. The business behind buying and selling beauty is HUGE. From the minor "i just want softer skin" with a lotion, to "give me a new chin please!".
Makeup isn't the entire problem. It is just one of the many different things out there (which happens to be pretty easily obtained now... the poorest of the poor can manage a few bucks to get some cheap makeup), it also comes with few risks (so, no wonder it is as widely used as the easiest and most effective way for a person to look better... actually getting and keeping and taking care of healthy skin is a lot harder than brushing on some powder before going out).
Then again, is it a problem? It sometimes seems to be with the cascading effect which happens as people keep trying to present more and more idealistic beauty (going beyond reality and even makeup, into simply graphic art and "touch ups" with a digital artist playing a big role in reforming a person into something which sells better on a magazine). That extreme probably creates unrealistic expectations and views of how the world is in some. But, by and large, moderate use of makeup helps hide a few flaws and give confidence boosts.
I think there is a balancing act between "learning to love who you are" and attempting to "show outside how you feel inside"... both often expressed ideals which are very much opposed to eachother.
