All fair statements below, I'd say.
Right, the only price which suits anyone's convenience for an email client these days is "free". Although a PMail user since 1990, I do recall paying US$50 for Eudora back some years ago, as an experiment. That seemed quite within the frame at the time, but that was then and this is now.
I know that Pegasus & Mercury have been a mission and a calling for David H., long since. And I also remember at least some of the struggles over the years. Some time ago -- funny that, how so much nowadays seems "some time ago" to me -- apparently there was some backstage shuffling around to fund an update to TER, and on a different occasion to assist David in his rebuild from what I took to be an abrupt hardware failure of his production server.
David has tried, he really has. As have some number of you who keep this forum going. Yet the headwinds against what David is trying to continue doing blow incessantly and relentlessly, punctuated from time to time by eruptions of discontented entitlement over this, that, and the other. (Not from you, Joerg, please understand, but from your users, who, as you say, "are not interested in any explanations".)
I also recall -- from better times -- Thomas Stephenson's (R.I.P.) excursion to visit David in Dunedin, and the lovely photos he posted on his website.
As for Michael's "we absolutely must know about them": oh, I have continuing annoyances with TER in text mode, but I just live with them, since I do understand the situation when it comes to funding updates, and I infer that you're referring to "fancy", not text.
I hope that development can continue to go on, and on, and that we won't be looking at turning down the lights and putting the cat out anytime soon. Yet I also know that our numbers do dwindle, and that the appeal of some 10-15 years ago for committed annual subscribers did not meet the hoped-for yield.
Perhaps we will yet endure.