The office where I work in central London, UK has bike parking for 300 and only eight vehicle parking spaces. We also have a fitness suite. There's two (male and female) locker rooms with showers, towels provided, a drying room.

At least one of the green building standards doesn't give you the top rating unless you have provision for active travel, institutional investors won't buy your shiny new building unless it's rated "Excellent" or "Platinum", tenants are looking for added extras which encourage their staff to come to the office rather than WFH.

And Westminster Council charges business rates (property tax) on parking spaces.

Manufacturing plants? Usually if there's a changing room there's showers

Used to work at a tire factory and we got paid $1.50 a shift on shower time. I absolutely needed it with how filthy i would get each shift

Many white collar offices have gyms.

The building I worked at in the Chicago loop had showers for bike commuters. Might be a big city thing.

As someone mentioned, gyms. I biked to work at one of my previous places, and if I wanted to shower, I'd head to the on campus gym. That gym had stalls, so theoretically ou could talk in the shower, though I never did.

Office I worked in had shower rooms. I did bike to work but never showered there because eeewwww.

Porn

My last two offices had showers. No communal room, but the thing I remember most about the last one is the hot water being pumped from the furnaces of hell itself. It took so long go get there, and was so hot once it did I can't think of any other explanation.

Mines and quarries