Activision was the final nail in the coffin for Troika. They could have avoided Troika's death if they didn't lock out the developers from the product for months. So yes, they did cause Troika to collapse earlier than it would have otherwise. They sabotaged the game, they killed the dev.
They didn't sabotage anything, they lived up to the terms of the contract to which Troika agreed. It's on Troika for agreeing to do too much given the time they were allotted.
While the later might be true, Tim Cain wrote in his section of the book "Gamers at Work": "First, while the game was held until Half-Life 2 shipped, we were also not allowed to keep the title in development." and "Second, while our game was being held, Valve continued to make improvements to the Source engine — improvements we couldn't add to our game." So not only did Activision decide to release the game on the same day as the much more anticipated HL2, they should also have been aware that it used an older version of the engine which wouild be unfavorable in comparisons. That was just stupid! A few more months could have helped a lot, but then the Activision QA was a joke anyway, otherwise I wouldn't be fixing stuff 13 years later!
Also don't forget to blame Valve. If they wouldn't have delayed HL2 over and over again because Gabe Newell only cared about making Steam a monopoly as fast as possible, Troika wouldn't have needed to update to new Source engine version restarting parts of development all the time. And not only that, even today the Bloodlines version that is sold on Steam will not work on a decent computer without either some serious tweaking or installing my patch, so this might be another reason why the Steam sale numbers are low. I wonder how sale numbers are on GOG without any DRM and the patch included!
This is an example of why using other people's engines is a bad idea. You are putting your company's future in the hands of another company, when they have no reason to care about your company's future. As if dealing with publishers wasn't already like dealing with loan sharks, you add even more risk on top of that.