There’s this thing in economics, the Law of Supply and Demand.  A lot of folks understand the painful parts of this - when demand is strong prices can rise and competition can enter the market. What is often overlooked is the flip side, the notion that demand rises as prices fall. The law says you can sell more products at a lower per unit profit, but end up with more total dollars in the bank with a lower price. What’s more, with digital products it costs exactly the same to produce 150 “units” of a product as it does 100.  
That is, if TER lowered its membership price, they are likely to make more money. Also, lowering the price is a disincentive to competition entering the market.