ED has had continued development since it was released. Whether you liked that development is irrelevant. NMS is not 10 times bigger since release. Not even close to that. Each update has not been as big as you think, they are all very basic when it comes down to it.What you say is true, and considering how Hello Games could turn the initial rage in the the present love somehow they mastered the situation. The trick here are the facts not the words.
Hello Games released a game in 2016 and 3 years later this game is 10 times bigger than the initial one. We can't say ED had the same fate. After one year from the release FDEV started working on other projects and left ED grounded in the corner for whatever reason. All other Frontier games did not have the delays that ED had and is still having.
As to delays for other Fdev games, look at what is added to the these. They are small things that have little impact on the game, things like adding a ride to planet coaster, or adding an animal to planet zoo. I'm not surprised it doesn't get delayed as it doesn't add any new gameplay mechanics. ED is a very different beast and is very difficult to compare the two. Also we don't know if features were cut or not as they don't tell you a year in advance what is coming.
Beyond was a very different beast. They told us over a year in advance, probably not the wisest thing to do as inevitably things get cut. Do you think other games companies don't cut features from updates? It happens all the time, why people expect Fdev to be different is beyond me.
As to fleet carriers we know roughly what was coming, I will be interested to see if any of that has changed and if they have done more work on them. My hope is that they give people options for smaller carriers (I don't want all those landing pads).