If the majority of your revenue was from the small & medium accounts, why not just create a single plan, remove the lower plans entirely? Why continue with the personal plan if that resulted in higher turnover and less desirable customers?
Because the two smallest plans, while having high turnover, have also ultimately generated 65% of our revenue. So at this point, they're still a very important part of our customer base.
As far as only offering one plan, it simply doesn't make sense for us. Our costs go up based on the amount of usage, so it makes sense for the price to go up for customers who use more resources.
There's also a psychological aspect. Although I don't think it's as important on the lower end, as opposed to the people who believe they're actually being somewhat frugal by not choosing the (often mostly superfluous) "deluxe* version.
