Well not only modern day RTS lack base build, they do even lack explanations how the strategy works.
Modern games like Dawn of War 3, Act of Aggression, Forged Battalion or Halo Wars 2 completely forget to explain unit counters.
Compare explanations form older games each has clear explanation in game or manual.
Star Wars: Empire at War
http://eaw.heavengames.com/units/
Starcraft II
http://vaughnroyko.com/sciicounters/
The Battle for Middle-earth
So even if you have no idea, you can check by Imperial Star Destroyer
Strong Against
Corellian Corvette, Corellian Gunship, Nebulon-B Frigate
Weak Against
Y-wing, Mon Calamari Cruiser
http://eaw.heavengames.com/units/?a=Star_Destroyer
Let’s compare it to Terminator from Act of Aggression, there is simply zero clue how you are supposed to take it down.
The gameplay experience from new games was quite awful, I mean you play a game and encounter units where you have no idea how to deal with them. By old ones you just check in game description, manual and its clear very fast ok, that’s an AT-AT Walker, I need Plex Missile Soldier.
In modern game you encounter combination of upgraded M1A2 Abrams that are instant healed by Hercules, Act of Aggression provides zero explanation what they intended.
Result is quite clear, while in Empire at War you see people combine and try out different combination of units, in Act of Aggression you merely see people use from 3 factions, 60 units, only 1 faction with combination of those 2 units Abrams/Hercules.
You can very good see how popular this lazy “modern day” approach is.
Even today over 2000 people play Empire at War, while DoW3, FB and AoA come together to max 300.
Its actually no wonder why modern day RTS have failed,
but somehow their publishers and developer don’t figure it out.