Well, I see the point, but let me put it into perspective: Right now, in my Steam library, I see six update notes for six different games. All hotfixes and small patches. They include stuff like: "Players can now damage signs with melee weapons.", "The auto recruitment feature on settlements can now be disabled via a checkbox." And these are the actual game changes, the rest are mostly fixes for obscure crashes.

While I do tendencially read some of these, I often do not. I will generally read through the bigger ones. However, even here I am a rare breed. Thing is, if you appear too much, people just stop reading, because they know the additions are just minor and they rarely even affect the average player.
Which brings me to the core, people here are invested in the game, most crave every bit of news, as this is relevant to them. However the average player does not. He will come back and regain interest for bigger things and he has stopped playing for certain reasons, he would want that addressed, be notified about it and then come back.
If that one sees constant small updates he will complain that Larian is spending too much time on unimportant stuff, while issue XY remains unaddressed. Plus players crave content, a new checkbox for recruitment, even if it is a good addition, will not justify another playthrough. Now hundred checkboxes, put into a large patch, this is different, this can alter the game.
Further, as said earlier, they might not have much to announce, yeah they could make a Twitter post every now and then, what they are working on, but they might announce something ever so small that they will have to cut again or delay, the reactions would again be unwilling.

A recent example is BFV, they started with announcing "great" features that never made it into the game, even though it was almost finished or the team worked on a solution for months. Later, when the players craved for content that everybody knew the devs could not deliver, they started to communicate more, but since there was nothing to share they started to tweet something along the lines of: "In two week's time we will announce the date of the reveal of our planned upcoming content." So an announcement of an announcement of revealing content that might make it into the game at some point later. Naturally that did not go down too well.

So Larian seems to like larger patches and small hotfixes and naturally everything takes longer than expected and longer than the players can wait for. So they will receive some flak, but would receive exactly the same flak if they did it in other ways.