I think the Bitcointalk is just a small percentage of their reach. What I mean is that this forum might not be their main focus probably they are busy on other platforms where they can get more players than here but I think keeping their ANN thread active from time to time would do much good as people will know that they are still active and operating.
On the other hand, I think Bitcointalk is one of the greatest and biggest forum so far, I stand corrected and there is no harm in keeping their Ann thread active because I'm sure that they already got some clients from the forum.
When it comes to Bitcoin/Cryptos and Blockchain, you are right with that but when it comes to general discussions, there are bigger forums than it. Reddit for example. Indeed that there is no harm on keeping an ann thread active but it can only bring benefits to the company who posted it and maintained it and its reputation.
I check the true flips ann thread here >
https://bitcointalk.org/index.php?topic=5069872.1600 and it was still open although the last post are made last year. Maybe if someone can bump it, many members will start talking about them and later on it will be noticed by their forum representatives. That's going to be the time they will make a reply and be active again on this forum. I check their website as well and it was still operating normally. We must only be careful as @gamblingbro didn't get a response last time about its problem.