Answer:
Because Stalin was not ruthless during this mission, this means no harm, he only has good intentions.
So he decided to introduce the 5 year mission in Russia/ USSR to build up its industry so it could defend itself from attack by countries in the west. Stalin wanted to modernise factories in the Soviet Union to increase the amount of goods produced.
This was planned through the promotion of higher growth rates, better income distribution, and also a significant increase in the domestic rate of saving.
