Bitsler had a long running signature campaign as well as promotions in the past, I was one of their signature campaign participants for more than 2 years IIRC.
Every start must have an end, maybe they think that what they spend here is more than enough and moving to other places to advertise.
They run two different signature campaigns. The first one is a long one, that what you mentioned here, but I'd like to correct you a little bit. It lasted for 4 years, not 2 years.
Bitsler Signature & Avatar Campaign (Closing Friday). This campaign lasts from August 2016 to January 2020.
They actually came back with another campaign.
Bitsler Signature & Avatar Campaign (Paused). It starts in September 2020 and ends in November 2020.
No one knows if they will come back to be actively promoting the site again in this forum, but it is absolutely possible because if I remember it correctly they relaunched the signature campaign few years ago.
They already came back with a signature campaign once, so they might run another one in future. After a long time of inactive, now they start to be active again in the forum, it can be a start for other advertisement types.