If anything, that kind of "advice" only adds to the frustration. I did not buy a DYI kit, I bought a product. I want that product to work. I may put up with deficiencies like that - in fact, I do not even use CalDAV - but I am a minority. Your Joe Average will look at an unfinished product and simply turn away.

There are so many things wrong with that statement that it is hard to choose where to start. I did not say a single bad word about Sailfish. I said it about Jolla. And support? "You are doing great, everything you do is perfect, you are the best!", versus, "Now that was a bit silly, wasn't it?" Which one is more useful?

I stand corrected. "Not a large enough subset of the already dwindling number of Sailfish users need/want..." Better?
Yes, I assume there that only existing Jolla customers would consider buying one, an assumption that I am willing to bet money on is correct.