Actually, sending the least experienced technician to your house first is an intentional tactic. My father is a retired HVAC person of more than 40 years. He used to work for small family owned shops but the big companies (like gas companies) began buying up the shops in various areas. Then providing HVAC service plans via your gas bills.
They would load up on young guys and keep one or two old guys. They'd always send the young guys first because they were paid about 1/5th of the amount of the old guys per hour. If they fixed things correctly, then they made more profit. If they didn't fix things, you still paid the hourly rate anyway. After the revolving technicians of various skills attempted to fix (and charge you anyway), they would eventually send in the senior guy to actually perform the repair.
Most of the repairs are easy and minor. Nowadays furnaces have circuit boards with LED lights indicating the problem. So it's mostly just replacement of a known part. So most of the time they made a lot of profit by sending the youngest/cheapest guys.