Commencing Stopwatch is too powerful of an item to be a mastery.
Diving becomes incredibly accessible when you can trade aggro with a single click. Paradoxically, diving becomes inaccessible if your oponent has stopwatch. This phenomenon creates a feedback loop where players are forced to take stopwatch just to be able to compete with other players. It is now uncommon for less than three players on each team to have commencing stopwatch as a mastery.
The mastery itself is worth 600g without its additional cooldown passive and the item can be cashed in for 240g if you happen to not want to upgrade it.
If you go Inspiration in the secondary tree you can always just grab magical footwear regardless of what champion you are playing. Everyone needs boots, and you save yourself the standard 300g if you pick it. The inspiration tree is too affordable and too universally accessible as a secondary tree.
Targons and overheal furthers this stalemate by creating a laning phase that devalues trading. Permanent shields and sustain turns botlane into an uninteractive farming simulator until one side is outnumbered and dived for first tower.
Inspiration needs to be changed by making its options more unique to each game. Stopwatch, Biscuit and Footwear should be placed on the same line so that picking Inspiration as a secondary tree is less of a necessity. Targons needs to be made into a melee only item (with maybe the exception of Thresh) so that it can not be abused by ADC's and Overheal.
Riot may have succeeded in making the games longer but they are no less one sided than before. This meta has simply made each game more tedious and less interactive for everyone.