If it mattered enough, the US government could ABSOLUTELY afford $330 billion to get everyone a pony.
It's not that tremendous things aren't possible, it's that we aren't doing them.
Doing some quick checking, food for a pony is ~$1-2k per year. Lodging is $2-3k per year. Basic preventative veterinary care is $1k per year; if the pony gets old this could get a lot more.
That's $4-6k a year for upkeep, and ponies live for 20+ years. So the actual cost of a pony, even with discounting and whatnot for future dollars, is probably at least $50k, not $1k.
My guess is that these ponies would be kept in horrible conditions similar to the way domesticated cattle are raised for milk and meat. I would hazard that all of our assumptions about the actual price of ponies and maintenance would come down if we all needed to have a pony, and would come down by a LOT.