similar to chess
Not at all. Chess is 100% deterministic, with only two possible outcomes: Either one side has a winning strategy, or the game will end in a draw. Which one it is is still undecided, but the number are getting crunched fast. In a few years we'll have an answer.
Sins however is nondeterministic: Starting positions, random resource mines, trashmobs", random maps, network latency and so on.
Anyhow, the key to success if building a big fleet fast. It feels lie 99% of the players don't build a fleet early enough. They'll get swarmed by players that do build a fleet. What point is #1 economy rating if you don't have a fleet? Sure, you can build ships, but you'll only feed your enemies capital ship that will sit right next to the frigate factory, picking up everything that gets built.
I've won plenty of games as Vasari where my enemy went for economy without having a fleet.
Fleet, FLEET, _FLEET_!!111!!one!!eleven!!!!
The most important thing.