"About the 'vision' comment, at my work there is always a support team, they get feedback from users and we never give a response 'it is our designer vision or our dev leader vision that things are like this'."
Yeah you may not actually say those words exactly but I've many times heard support staff essentially state the same thing. They might say "sorry the product is not designed to do that" or "we don't sell that here", e.g. if you go to a car dealership and what you really want to buy is a helicopter, they will say sorry we don't sell flying cars, these cars were not designed to fly. Maybe they don't use the word "vision" but it's all the same, if you decide you are going to build a car a certain way then you have to stick to that, once you decide to add helicopter blades then it's a different product for a different market. So you could just exchange the word "vision" with "plan" if that helps to understand it.
For a big project, yeah, they can obviously afford to do more and to put more features in a product but they still have to draw the line somewhere.