They likely also have lower costs due to eliminating the middle men whose job is to translate text on the screen into words spoken to a customer.
So their lower costs could actually be legitimate.
First, it was phones. This happened in the early 90s. Then it was internet which was largely finished by the early 2010s. The only exception for this is that online price-comparison websites have added back some distribution costs...but you still need to spend on marketing if you are online (generally speaking, online ads aren't cheap, I know insurers in my market that have moved away from price-comparison/online advertising because of the cost).
Large insurance carriers (think Geico, etc) with enough market share (and captive agents) have the vertical integration that eliminates the middle men, but there is a whole world of insurance that most people don't realize each taking their cut.