I can't officially tell you the reason. But I can tell you why I didn't choose "true" white several years ago when my quartz kitchen counters were installed. In general, kitchens have a lot of task "down" lighting. A bright white counter reflects that right back up at you--brightly. I went with an off white because it felt more calm, less clinical, while still retaining the overall light effect I was going for. Sorry, I'm not great at taking photos :)

It would be hard for a quartz manufacturer to have every single version of white! Each brand usually has 2 bright whites and then equal variations of all the other colors.

Did you check with the store that all the available samples were on display? Where any samples out on loan to customers?

I’m not sure how you are characterizing the color choices. If you categorize anything with any movement or pattern as off-white, well, there may not be much market for completely-plain-with-no-hint-of-other-color-white.

I think the faux marbles have been popular for a few years now so each maker probably has a couple of those because they sell well. And those tend to have grey, so maybe you think of them as off-white?

And some people prefer a pebble look as it hides stray dust and crumbs a bit and/ or they like a bit of sparkle. So every maker probably has at least one of those options.

And at that point they have got, what, five to seven white options? Not everyone wants white. So I would think they can only dedicate so much of their line up to the whites.

That’s my thinking. But you could always ask the shops you are looking at. I am sure they have a much better grasp of what sells than I do.

Solid white countertops have been in style for 50 years as Corian Glacier White proves.

I characterize off-white as not being true white, most of these look like a bit of a cream color. I’m not looking for a solid plain white counter but one that has marble look veins, they can be grey that’s fine but the white part is true white and not “creamish”

I think it depends on what one's looking for

I was looking for a greenish off white for ages, couldn't find the right(to me) shade, so it seemed to me there's so much true white, and cream, and marble look, in short everything but what I need:)

I think it just takes some time to find "your" color, whatever that might be

Do ask to take samples home, and look at them in your light, with your other materials. Stores have different lighting than your house does. Look at the whole slabs as well, of course.

Joe, I think we are making completely different points. I’m not saying plain white is out of style. I’m saying there are only so many people who want plain white. So only so much of a line can be dedicated to it.

The quartz manufacturers would not be dedicating such a large portion of their lines to various "whites" if they were not selling them. They make what people want and buy. Right now, lighter countertops are hot; 15 years ago, everyone wanted black or dark green with their white cabinets. It is all cyclical since kitchen designs became "fashion", not semi-permanent.