Wait staff in many states make below minimum wage, with tips expected to make up the rest. So I always tip wait staff and will still tip when theses laws change.
I also try to tip everyone I can when I have the means. Yes, I’d tip janitors, their job sucks, as do most jobs where you have to deal with the general public, and they’re underpaid.
The "expectation" of tips making up the rest is really just an expectation from the business that you will needlessly subsidize their payroll, in all 50 states the employer is mandated to always pay the minimum wage even if zero tips are earned https://www.dol.gov/general/topic/wages/wagestips
I say tipping is unnecessary because there exist a few states like California who ban the practice of paying a lower "cash wage" and allowing businesses to keep tips for themselves. Anecdotally, I notice that typical restaurant bills in California are not any more expensive than nearby states like Nevada, Colorado, or Arizona.
I also try to tip everyone I can when I have the means. Yes, I’d tip janitors, their job sucks, as do most jobs where you have to deal with the general public, and they’re underpaid.