I have been 'playing' OU for a while, relying on dex analyses, metagame discussion posts from experienced users, and tournament replays to get teambuilding going and understand the tier better. While I enjoy playing / watching OU games and I fully acknowledge it as the most popular tier in Smogon, I personally struggled to keep up with the metagame state.
This is partially because I don't necessarily main OU on a consistent basis, but I feel like the metagame trend is quite volatile. A few months ago when USM came out, I just stuck to casual ashgren teams with some Spikes support to get things going. A month later, I see Gastrodon (I know why this Pokemon is relevant but) and other niche Pokemon that rose to OU by usage today, and after a while, some Pokemon rise to S rank on VR, drop, and go back and forth. I came back recently to see Mega Alakazam being one of the best Mega Pokemon at this point.
How should I view OU? Is it a tier that trends tend to be so volatile and is based on a new Pokemon checking an existing threat, becoming a prominent threat itself, and causing introduction of unpopular / niche / unviable Pokemon to rise, and just having this cycle repeated? If not, what view on OU will help me keep up with metagame that changes quite frequently?
I apologize in advance because this is not a simple question at all, but I felt like I'm definitely not the only person who has the aforementioned concern when attempting to actually learn OU. I know the community is a good place where entry barrier is non-existent, but I am seeking a way to get competitively better. Thanks.