Add in Defense upgrades so at least some sort of armor buff can scale with the ever increasing damage upgrades.
This is largely Inspired by PVP and some people may think that is irrelevant to the base game and you are entitled to that opinion. But as it stands PvP is shipped with the game now as a scenario but it is in need of some special attention and balance.
early game each defensive technology unlock is super powerful but as damage and offensive technologies scale every turret and player ends up becoming a Glass cannon capable of Dealing immense damage but unable to take any. This makes encounters last shorter and shorter as time goes on.
But, If a team was able to invest in defensive upgrades that being armor buff or some over shield with unlimited research as well, then there would be some hope for them to scale evenly.
- Building/Turret armor upgrades
Power armor upgrades
Vehicle armor upgrades