Long story short, a lot of people have quit, change in player focus towards xp gain & money gain over "fun", lack of mini game updates and rewards, no more bots, and few more.
People still play mini games not just like back in the day. Most notably the games that still run on spotlight and from time to time are, Castle wars, Soul Wars, Stealing creation, Pest Control, and Fist of Guthix. Note that in a lot of these people will just afk for thaler, notably when on spotlight. Search for fc's and clans. These are small communities that remain. Fastsc for stealing creation. Cw clan chat sometimes hosts castle wars games. The rest of the mini games usually only run on spotlight. It sucks I know