We are in the process of improving the data health of our database and have tons of events dating back over a decade, all of which had never been inactivated. While there is a way to inactivate Events, you can only do it by going to the individual page and clicking 'mark inactive' there. This is very tedious in our case where we're dealing with a large backlog. My recommendation would be to add the criteria in Admin>Globally Change Records>Events to allow a change of multiple events to inactive at once.