To what extent did the combination of technologies make indo-european migrations possible?

The Indo- Europeans originally came from the Steppes. They were nomadic and pastoral people who tamed horses and rode chariots. They lived in tribes and spoke Indo-European. There way of life may have contribute to the reason they migrated because they probably ran out of resources. Historians and scientists can trace their migration by the languages that were spoken there. Indo European language family can be traced back to modern languages such as English, Spanish, Persian, and Hindi.

Pressure and heat that's what i think( don't report if wrong)