Originally Posted by toplel
When I was in a store yesterday the staff remarked that blue blazers were very difficult to match pants with, that in 2016 you could not longer one with chinos because it was too "preppy".
Okay. Some strangers at a store told you a couple of things which have caused you to question what you thought you knew about blazers.
I'm a stranger to you. Let me tell you a few things of my own.
Navy blazers are not at all difficult to match to pants. You can wear a navy blazer with chinos. It's a classic look, although as a general sort of rule, it works best on younger men. Past college age, and a pair of wool dress pants will often tend to be a somewhat superior pairing. Your idea of light grey pants with a navy blazer is about as classic as it gets.
Mind you, I'm 53 years old, and in certain circumstances I wouldn't hesitate to wear a navy blazer with a pair of Nantucket reds. In the winter, I sometimes wear a pair of camel colored cords - they'd go well enough with a navy blazer, too. The relevant point being that it's about as challenging to find pants that go well with a blue blazer, as it is to find a tie that goes well with a blue shirt.
Naturally, virtually no garment is "foundational" for all men. But for many men, a navy blazer is, indeed, a wardrobe staple. They are sort of the equivalent, for many of us, of what the "little black dress" is for many women - a highly versatile and accessible item.
Oh, and the next time you go to this store, and the sales staff tell you that "Solid navy blue suits and medium/dark grey suits are too preppy, and too difficult to match with neckties," just smile politely and ignore them. Because working as a salesman in a store doesn't automatically make one's sartorial opinions particularly valid and insightful.