Over my lifetime that number would have varied significantly. There have been years when I did a lot of cycling but put almost no money into it and there have been years when I did a lot less actual cycling but paid a lot more for the cycling that I did. Looking back, I'd say that the fun factor has remained the same. To me one of the beauties of the sport is that you can make whatever you want of it.
Other than occasional tire replacements and patching tubes, virtually all bicycling expenditures are optional or, like chains and cassettes, can at least be deferred. Many of us spend a lot of money on cycling specific clothes and fancy wheelsets because they make us feel better. That's fine - I do it too today, but I really don't need that stuff to have a perfectly enjoyable time. I hope that I never forget my days of piecing together bikes for me and my family from bits that I salvaged from around the subdivision on garbage day.