Why do skilled and professional workers generally receive higher wages than unskilled and semiskilled workers

Skilled and professional workers are generally paid higher than the semi skilled or unskilled workers. This is because of the fact that Skilled and Professional Workers don't need any training to do the job. They have already educated in the field of their expertise that they don't require training. So because of this fact, they are paid higher than the semi skilled or unskilled worker, because semi skilled and unskilled workers require job training.

Training is the department in all organization where huge amounts are spent. So if already skilled professionals are hired, the cost of training for the company would decrease and they can hire the skilled workers at a high wage rate.

Also it is the game of demand and supply. There are usually less Skilled and professional workers. So the supply is less, demand is high. So their wage rate increases.