Weed is 10-15 times than weed in the 60's?

Yes it surely is, due to people wanting a stronger hit of THC or "high" effect. Since weed is more expensive than gold people are paying a small fortune for weed that can knock you upside down.

Most weed in the 60's was grown naturally "bush" with the help of tender love and care from the sun which gave the plant a small dose of THC.

Most growers now use Vitamins and Supplements to richen their crops (in the soil) for a bigger hit of THC, hardcore smokers are paying for the stronger THC high.

Which therefor makes the weed stronger and regular consumers are paying for that quality and not quantity.