Quite a lot of mods have migrated to newer versions of Minecraft like 1.16.5 and 1.18.2. Some mods keep updating pass those versions to follow Minecraft updates.
However, a lot of cooler mods are still stuck in 1.12.2 or 1.7. Also, some players don't like the new tech mods (like Create) and new mod launchers (like Fabric)
I now always play new Minecraft versions if possible, and after trying out 30+ modpacks across 2 years, I ended up making my own that I can enjoy.