Your numbers are interesting, but the average attendence of US churches is about 200 while the average membership is much larger.
Your numbers are true for a church of 100 but that is not the norm.
Only about 20% of members of an average church attend regularly so if there are 100 in attendance then there are likely 400 to 500 members. That would make your number of $65000 actually more like a quarter million on the low side. Surely with that income a pastor could support himself, the property and have some left over for charity.
The median membership of churches in the USA is 76. That means half of the churches are larger and half are smaller. It is better than an average, since there are huge megachurches that make average (mean) a less useful number. Most American churches are under 500 members.
The same with disposable household income in America. The median is just under 27,000. We know that those who make huge amounts more than that would throw off the average and make it significantly higher.
As to the idea that non-attending members give, I’d say that doesn’t happen, and I say it from long experience.
More than that, they don’t TITHE. So the $50, I’m talking about as a tithe is generally ten or 20 bucks.