Most people in our age range have families and lots of ties and commitments. We recently booked a weekend away with 7 friends and for most of them it was the only weekend in March they still had free. Birthdays, kids trips, judo contests, blah blah..
For me as an expat needing to travel for it, I complained that it was too far away in the future to know if it would work to fly over (eg important work commitments like trainings in the adjacent weeks)
I can't really blame them but as a childless single it's boring yeah. Good thing I have some nice social communities with similar people.