Well I do indeed appreciate that all this stuff exists, but the defender has access to all these tools also. Defence is always a stronger position to be in, in all RTS games. However generally you have to defend multiple locations at once, which requires you to spread resources. Currently this important point becomes moot as soon as the Population Pool is depleted, you only need to defend 1 location and defence becomes very strong.
If your hypothetical matchup has two literally identically skilled players with literally identical forces and literally identical funds, then the victor is going to be a flip of the coin anyway, so does it really matter?
The answer is to either get more skilled, have better forces, or have better funds.
I'm still curious what exactly this stalemate does, I personally haven't seen it. How does it determine who wins if it occurs? It would make sense for the defender to win in a campaign game, but in a skirmish game how does it determine the victor?
It's a STALEMATE. Imstead of a red "VICTORY" or blue "DEFEEAT", it's a blue "STALEMATE". No one wins.
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Neither the campaign map nor the RTS map builds any naval units but Transports, so yes, it is no good at defending itself from any Naval attacks.