At no point did I say it was simple. I'm a programmer too, I worked with Java for a long time and I know little about Unity and C#, enough to know that it's not really a puzzle, no matter how well it's structured, it's still basically a total rewrite of all the components.
However, what I said, and I'll say it again, if the updates were smaller (include fewer changes), then it takes less time to deliver. I understand that smaller updates are less expressive, they have less impact if you think about marketing, but I think that at the moment it wouldn't be a bad solution, it's better to wait 1 month and receive X than to wait 3 months to receive X, Y and Z. At the end of the 3 months, delivery is the same, but because they are more frequent deliveries, existing players have a greater sense that things are moving forward.
About updates where part is old features and part is new features, that's fine, it would only take twice as long to deliver everything that is old since half the time would be for new features. And I honestly can't understand what the controversy is about all this.
if you are a programmer i think you should know better. or maybe for games it´s different. it is not like you have a ton of small parts that you can add to the whole structure any time you want in any order.
there are lots of dependencies, which is why it makes no sense to insert the screws before the motor is ready and in place. neither do you fill in oil or gas before the engine is installed.
also red mentioned that each update is followed by weeks of bugfixing and maintenance. for us players it would be more convinient to get monthly updates, of course. but overall it would just take more time to reach the goal.
aside that don´t think that they can do everything themselves. i.e. models are done external, not by red and his team. i think the same for animation, not entirely sure though.