[2023] Why GSG stopped at being dead simple and refuses to add any additional complexity to the game?

I'm gonna give you a semi-official answer to this too.

They refuse to add:

someghing that radically expands gameplay variability like changeable support tools, new classes, new types of enemies and so on.

something that radically expands gameplay depth, like haz 6, 7, new difuculty modifiers, 3,4 of them per mission.
meta change that shuffles meta from bottom to the head, thing I was using 2 years ago still exeptionally good.

Changeable support tools go against the design idea. We want the four classes to be dependable and recognizable through their support. What is the driller gonna do if you take his drill? We have four classes in a four player game - that is what the game is designed around. Adding a new class would mess up the balancing. Ever played an MMO when a new character comes out? There's be tons of games that would just be 4 x NewGuy, not to mention the amount of stuff we'd have to make - a whole new set of primary weapons, secondary weapons and so on - not to mention frameworks, overclocks etc. New types of enemies are coming.

Haz 6 and 7 would be for a very small subset of people. Currently, maybe 10% play Haz 5. Adding Haz 6 would be a subset of those since a lot of people are comfortable with Haz 5 - and adding Haz 7 would be for a subset of that subset. Not to mention the extra toll it would take to balance two extra difficulties.

Regarding meta changes - it's just not that kind of game. We're not a big team maintaining a live shooter with constant events and changes to everything. We have a core game loop that we really enjoy and that's what we're building upon. The framework of the game is there, and we're working on adding to that with the seasons.

Thanks for your feedback, though!