They think these higher tiers are gold plated, charging extremely high prices for 50Mb+ service.
Price is king, always has been. They will not see widespread adoption of these higher tiers unless they bring the prices down to a reasonable level.
Or install low caps or metered billing on those lowers levels. Charter's 60 Mbps Docsis 3.0 tier has no cap vs 250 GB for their 20 Mbps tier and 100 GB for their 5 Mbps and 10 Mbps tiers.