TBS has been in decline for years with few 4x notable titles coming out such as Rebellion, Sword of the Stars 2, Endless Space (this one is extremely good), and Civ 5.
Jagged Alliance 2 was pretty bad and disappointed lots of people.
About XComEU, people have mixed feelings, while Firaxis tried to simplify the game so they appeal to a much higher audience ; it surely upset the die hard fans of old XCom series, but we must be aware that the market and the audiences are evolving and that there are very rare cases of big succes for Indie titles (recently Project Eternity which is a mix of Baldurs Gate, Icewind Dale and Planescape Torment got over 4 million dollars from Kickstarter).
Xenonauts might go viral and become a widespread game amongst both new and old players, but this is up to us, the pioneers to spread the word around and also help the dev team optimise the game properly so it can be released in good measures.