That's exactly what I was thinking. $5 to $7.20 in four years isn't ideal, but seems like so many other essential goods and services have increased at a much higher rate over that period of time.
When you move to an annual plan and then need to upgrade you will get charged a close out fee in addition to the extra plan cost. Yes, Google is charging you for the privilege of investing further in their platform.
Google Partners have been able to provide annual plans for years.
Starter: $5 -> $6
Standard: $10 -> $12
https://cloud.google.com/blog/products/g-suite/new-pricing-f...
This nets to ~45% price increase in just 3.5 years.