It seems like that changed somewhere around the turn of the century, whereby businesses started to decide that it was better to cut down on customer service, and in some cases, go so far as to ban customers. The first cases of this I recall reading about had to do with Best Buy, and specifically their policy of banning people from their stores who made a lot of returns.
I'm not really sure how it ultimately maths out - i.e., whether it's long-term optimal to drop troublesome customers or merely short-term optimal, and this was primarily taken from the perspective of retail.
As such, I'm sure the math changes a little for subscription services. However, I also recall my prior employer's support activity followed a power law distribution across its clients, so it wouldn't surprise me if a policy to drop particularly noisy clients is a net savings there as well.
There are definitely many customers you should drop, but business are not even that interested in retaining profitable customers. The problem is with the "over time".
Management are rewarded with bonuses and options that focus on the next few years so they are not really interested in how profitable a customer will be over the next ten years, only over the next one or two. Small businesses and family owned businesses are different, but for a big, widely held, professionally managed business the incentives are all short term.