Because employees have families and lives outside of work so can't just drop everything to go a team ski trip. Once or twice a year, sure, but more than that it's a chore more than a perk :)
My company is remote only and the money saved on office space has been reallocated to additional team outings and a longer runway. Constant outings sounds a bit overwhelming, personally.
Because that money is also just profit if it's not spent.
My last remote company had quarterly offsites, and sponsored at least a conference of your choice per year if you wanted to go to it. My current remote company hasn’t had many offsites (covid + clients in healthcare) but hires aggressively and pays significantly above market. Also spares almost no expense on employees. It’s hard to compare like for like though. How much of any company’s actions can be attributed to budget savings from cutting physical offices, as opposed to any number of other variables: decisions from leadership, market strategy, or quality of last funding round? It’s hard to isolate just the one cause, but it might be worth gathering that aggregate data to see if patterns exist.