Well, whether they do it because we demand it or not, my point was that they are giving estimates, though qualified ones. My main position on these things is that there are plenty of reasonable things to complain about, so why bother saying they don't give estimates when they do? For that matter, why assume they only give updates because we demand it? There is no proof one way or the other. I have never understood the need to exaggerate such things. To me, it just weakens the value of the reasonable complaints.
I also think, pretty much by definition, that an "estimate" is not a "sure". If they were sure, then they wouldn't be estimating! 
Now, the part about being wrong so many times means the method needs improvement - well, maybe so. And maybe not. Because that kinda implies there is a way to do so. And I don't think it would help if they "estimated" at yearly intervals.
This is what I tried to get people to understand when we had the monthly estimates and some people called for quarterly ones to deal with that problem. I told them to imagine they had always done them quarterly. We would still have, at this point, a 3+ year delay. No one would feel better getting a delay notice 13 times instead of 39 times because the total delay would be exactly the same! Actually, it would be worse. Because the most common info for updates came about the same time as the delays were announced. The old way gave 39 windows for obvious updates compared to 13 if we always did 3 month intervals.
My opinion is that, mostly, WT has to decide how long the estimate postpones things because only they have any idea at all of what is taking place. I'll push them to give us info more often, but not to give a particular timeframe for a new estimate.
I wish everyone could have been in treg to see how crazy it got sometimes, thinking a problem had been solved, only to have it come back either because it was so intermittent that it was hard to track or because some other problem could cause the same issue. It is MUCH better now, but that experience showed most treggers that this was a very difficult task. But while I can tell you about it, it isn't the same as experiencing it. However, you might keep in mind that a number of treggers, who use to make the same complaints as you, took a different view after they got to try it. Of course, there are those who automatically accuse these treggers of having stockholm syndrome, or being bribed, etc. They just can't stand anyone disagreeing with their assumptions. But most people, frustrated though they might be, should realize this pattern shows that there is more to the TB than most realize.
That would be fine if done from the start. But once you really think it is about ready to ship, as was the case back in early 2015, it doesn't matter if you goofed. People then expect to get updates from then on.
And that's perfectly understandable.
Bingo! Which is also why, as we get near each of those estimates, I start posting about the update being due. Though I'd still like a set pattern of at least monthly updates and anything in between is just a bonus.