Count me in on the "it depends" group. Our rule of thumb is "when we invite, we host and hosting is at our expense."
HOWEVER.....
i have a HUGE family (pushing past the 70+ now with neices & nephews & next generation) that would strip us dry of "free holidays" if given the option. Some I have a greater affinity for than others.

We have traveled with neices and nephews, at our expense, many many times and have no issue with paying for everything. When parents want to jump in on the action, then it's a different story.
A.Win's well made point of the perspective of personal wealth may come in to play. For us, it becomes a delicate mix of when to be generous and when to hold the line and encourage people to "give a little" for what they get.
Currently have a brother queued up for a trip for his birthday so he gets that for the price of the guest fee. He is taking guests and we are not traveling with him. Happy birthday bro! Had a sister recently that needed a family trip for a specific date window last fall at a specific location. I hooked her up with a trusted mega-renter that got her exactly what she wanted and she had no problem paying out of pocket for that trip.
Another sister is wanting me to host her extended family of now adult children and granchildren (7families and 30+ people) for this summer with a really short notice (got asked to do that last month). If that happens, she will get it for the cost of the GC's and MF's knowing I can flip those same reservations for triple that in rentals.
Sometimes we invite and host for free, sometimes it's for the cost of the Guest fee, other situations I straight up have them pay us at discounted rental pricing (family rate). And there are some that just get told "NO" because history already tells me they are going to change their minds 10 times and then cancel everything at the last minute.
Sadly, none of them understand or get the effort, planning and constant monitoring of availability it takes to get people where they want to go. There is zero appreciation for the process because none of them are owners.