Well you have a few choices courgeon you can drop the rope, stop the giving, sit back and see what happens and see if they finally step up (please be prepared for no one to step up!) and see if you can coax your current friends to see the need for balance. But the very fact you are having to do that indicates they are pretty crap friends/people in the first place if I am honest.
You can try telling them directly - I am getting tired of doing Christmas every year, can you do next year' but it won't change the fundamental fact that they are selfish people, and eventually they continue to be selfish people even if they offer do Christmas under duress.
But I don't fancy your long term chances with many/most of them, because these people have seen the effort and costs going into all of this hosting over the years, and they don't care enough for you to even offer even a few times to host instead.
The status Quo suits them perfectly.
You will get many questions once you stop and many confused and upset responses as you pull the plug. You may get anger, are you doing the same parties without us? What are you doing instead? Have we been replaced? You can expect direct self invites, 'we haven't seen for ages, we will pop in on Saturday night around 6pm'. Just in time for dinner no less. You might even find they drive past and see what you are doing (as my friends did) Emotional blackmail, I miss you/your hosting.
Over time your life might start to fill up with more generous and kind people, or it may not. What do you have to lose apart from a bigger bank balance?
It is a horrible feeling being take advantage of. It feels deeply anti self to be giving and giving and getting nothing in return. Do these people even care about you at all? Beyond your lovely invites and their full diaries? Do you matter?
I drew up a list of everyone and actually mapped out what was happening and that was very good, it was clear those that loved me back, and those that were using me.
What will happen next if you don't address this now, something bloody awful will happen to you (serious illness, injury, bereavement) and you will find out the hard way how little they care.
They will suddenly be 'too busy' and despite the years of investment, hosting and being a good friend to them it will count for nothing.
It is bloody galling and the friendship will be over anyway. Users are self serving by definition, don't expect them to care if your life collapses around you - unless you are prepared to plaster on a fake smile, dry your eyes and get back into the kitchen and hold court and cater to them. Invest in yourself and those that truly love you.
'Dont be a Dobby!!' as my kids say. How true, and how wise at eight years old
For those that haven't seen Harry Potter:
exploringyourmind.com/the-dobby-effect-and-feeling-guilty/