Anyone who can write them a cheque can also set up such a service themselves. All of the certificates are freely available in the CT logs, and every domain must

Anyone who can write them a cheque can also set up such a service themselves. All of the certificates are freely available in the CT logs, and every domain must have a reachable email address (or they risk their domain being taken from them). You can probably save a lot of money (and be less liable for violating spam laws) by making the free service opt-in, of course. LE just isn't interested in maintaining such a service. Sending them money won't make them interested all of the sudden; that money can be spent better on setting up an independent free alternative.