Some offices have cantines and many of them are terrible. I was a Dutch office worker for 10 years in different offices and ate all kinds of different things. Now I work from home and continue to eat sandwiches almost every day. I just like them.
As for the Chinese food. You need to go into a big city and eat it. Don't eat Dutch Chinese food in small villages or suburban areas. Both Rotterdam and Amsterdam have amazing Chinese food. And I bet you never even tried Surinamese food before..
And so did I when I worked there, but I made my own. If I forgot to do so, I nicked one of my Dutch colleagues sandwiches - they couldn't stand the cafeteria ones either.
Chinese food was in Utrecht and Amsterdam - it bore no resemblance to the food you get in London, and you never saw ethnic Chinese eating there, unlike in London.
I'm not trying to be racist about the Dutch people - I enjoyed working in the Netherlands very much. Except for the food.
Most people that I know here in the Netherlands prepare lunch at home and bring it to work or school. I work from home now and still usually eat simple sandwiches for lunch so at least for me it's not about "no alternatives".
It gives me more time to go outside or stop working early - I honestly don't want to spend (at least) an hour going out just to have lunch and then a similar ritual in the evening for dinner.
Might've been more palatable with better bread, but these were typical bad lunch sandwich bread buns.
That said, I can live on PB&J, especially with fresh PB and a good bit of toast.