Are you sure that CS:GO isn't just a less popular game than it used to be? At least on the esports scene?
Given the absolute minimal user flow needed to watch a livestream, I find it hard to believe that people suddenly can't find tournament streams when there's already extremely limited options to do so.
Accepting my claim I've been watching for 1 year, when I got into it was slightly more popular than it is now, and during the middle of that time it did hit a very high peak [0].
>Given the absolute minimal user flow needed to watch a livestream
That's the whole point: it was previously 100% effortless. If livestreams were on, they were on Twitch. You would go to twitch.tv, click the icon for CSGO which was 100% guaranteed to be on the front page, and the top streams were talented/personable professional players and/or tournaments with significant prize pools.
After the deal ESL signed to start streaming CSGO on YouTube, the friction to finding a stream drastically increased (because it had previously been a URL navigation and two clicks until you were watching a stream). Then, YouTube's awful discoverability and UI/UX compounded the problem of finding streams on the new, secondary source, but that's assuming you actually knew the streams moved to YouTube and didn't just start going to Twitch and finding drastically less content, and gradually stop watching.
Now, I'm not going to pretend my words are gospel or anything, but it's of serious consideration that the aforementioned peak popularity occurred in mid-January, very close to when ESL started streaming on YouTube exclusively (Feb 7 being the actual date [1]). Of course, there was a major tournament during this time as well, but this was a great tournament that you wouldn't expect to drive population numbers down so drastically as they fell off afterwards.
For context: ESL is a very large player in the CS:GO scene, hosting plenty of tournaments, the most popular online league, and even Major tournaments (of which there are only a few a year with increased prize pools, the highest level of competition, additional other revenue for teams, and, less quantifiably, prestige for winning).
I am not disputing what you say, but for future reference you can create a bookmark that goes straight to the CS:GO channel. Or follow the channel so it's on your follow list all the time.
I do agree that the split has impacted CS:GO, but a few new releases have shaken up the top tiers. (Player Unknown's Battlegrounds for instance.)
I might be in minority, but at least I do not follow any tournament schedules. If I want to watch live stream I just pop over at Twitch and see what's on.
This comment thread is the only reason I know everything had moved to YouTube... I had been wondering where the hell all of the tournaments had gone for the last few months... Open Twitch, click CS:GO, see if there's anything on has been my flow for 2+ years.
Given the absolute minimal user flow needed to watch a livestream, I find it hard to believe that people suddenly can't find tournament streams when there's already extremely limited options to do so.