There are soo sooo so many reasons Laks why what you think could have happened absolutely would never ever have happened. No company would buy IP and spend the money SD has spent and then react in the way you seem to think they should have.
It's just cost-value calculations at the end of the day. You can either spend resources to litigate, or just spend resources drowning them out in advertising, marketing, and establishing a far greater presence. Big competitors do this all the time, Pepsi and Coca-Cola. You literally have companies referencing the other's trademark in a negative light for an ad, making fun of them in Super Bowl commercials, and nitpicking each other's faults. But they don't launch lawsuits for minor things like that, they just twist it to their own benefit through marketing. And if you want a weird one that involves both Pepsi and Coca-Cola... Both companies actually manufacture Dr. Pepper. (Coca-Cola in the US and Pepsi throughout the rest of the world.)
The thing is that Stardock has a market presence using the "Star Control" trademark. So how an announcement upon a blog effects a multi-million dollar company is beyond me. The most it did was flash up as filler upon a few gaming sites to keep the staff writers busy. That announcement has faded away by now. To demonstrate...
"Sir! Sir! Mr. LakCEO!"
"What?! What do you want?! I'm busy! I'm three turns way from the Drengin parking half their fleets on one of my best worlds! What do you want!"
"The owners of the copyrights for the game, our acquired trademark was put on before in the past, have made an announcement upon their blog!"
"They are planning on making a game and referenced our trademark!"
"What did they call the game?!"
"... ... ... Okay... That's it?"
"Um, yes. That said it would be a true sequel to their old work, Controlling Stars V!"
"Okay... But, they ain't calling it Controlling Stars: Precursor's Ghost, right?"
"Um, no, sir."
"What did they post on their blog thing?"
"Just saying they are starting work on the project, sir."
"Just Starting? That's it? Any mock up screenshots?"
"Design documents, pictures of reference materials, a title graphic?"
"Um, no, sir."
"Uh, bad flip phone pictures of napkin drawings of stick figures?!"
"So just some text upon blog people are going forget about by next week?"
"Y-Yes... ? W-w-what do you want to do, sir?!"
"Well, I'm going to ask what I pay my marketing team for! Why haven't we spun this announcement in our favor yet!? Their customers are our customers, we just need to tell them where to go for the new, proper Controlling Stars product line! Make those marketing pukes slam out a bunch of stuff on all that social media stuff I pay them for and tell them to do a week long sale for 10% off on the pre-purchases! The customers eat that stuff up."
"But don't we want to do something about them referencing our trademark, sir?"
"Because people might be confused about who owns the Controlling Stars trademark?"
"What?! We've had the thing for years now! We got a website, developers logs, screen shots, a series of alphas, a working beta, constant feeds of stuff with our trademark stamped on it to all the news outlets, and loyal horde of fans already playing our beta... Our game is going to be released this year. It'll take them... what... two, three... four years to get something out? If they even bother with doing anything? By then we'll be in our... what... second or third run of DLC and ramping up development for the sequel? I ain't paying those blood sucker lawyers we keep around anything more, for a random blog post!"
"Yes, sir! Understood! I'll tell marketing right away!"
"Where are my pants?"