My wife's late cousin and their family were huge into the Live Steamers here in Los Angeles. Started back in the day by Walt Disney and others who had the money to put into it - definitely not a cheap hobby. To just get started if I remember correctly when I asked back in the 1990s it was $10,000-25,000 for an engine. Plus side is the hobbyists run their rigs on tracks in a park and you give killer free or low cost train rides to the general public but down side always seem to be repairing things.

http://www.southerncalifornialivesteamers.org/

A lot like care and feeding for older pinball machines .

Back to the question - it doesn't matter what the hobby costs as far as I am concerned. If it brings you joy and spending the money isn't cutting into your rent, mortgage, car payments, insurance, food, medical costs, savings have fun with it. There is always someone with more money than you and someone with less and each person can work out their own joy in life and not worry about how it stacks up with others.

Except for - serial marriage. That can be an expensive hobby after divorce and child support but then again life has it's expenses .

Past hobbies:

Comic books and collectibles were relatively cheap though possibly as much space if not more than pinball machines.
Coin op machines - use to run them - down to a few and have migrated away from them with the exception of one or two.
First edition books - was expensive and then as the market started dropping out got rid of some books, donated others to people who still collected.

Still collected:

Firearms - highly addictive and fun but ammunition is not cheap these days. They retain value but have stopped buying them because like pins, they tend to breed like rabbits.

Again it boils down to if it brings you joy and all things are being equal stay with it. If costs start to get crazy and impact enjoyment, well then the hobby just isn't fun anymore and maybe time to change hobbies .
Staying married to the same person for over 30 years has helped - costs of raising a family do cut into hobby spending though