That could be the problem! If you only call once a year, and you get turned down that's 100% turn down. If you call twice a week for a month and "only" have 3 get-togethers, that's almost 50% success and it's only in one month; that would be 36 get-togethers a year!

Call until you get what you want, people are busy. I'm retired so don't work, can get up and go/do/be anywhere at anytime. It's hard to get together with others though because they have complicated schedules and other needs and interests. Try not to take it personally.