Mcmaster is great, but it's important to point out there's no brand or product selection decisions. You pick your criteria and get exactly one option. It lends itself to a very different experience.
How would this work for cars or couches or headphones?
> How would this work for cars or couches or headphones?
This would be great for many things! I'm sure there are plenty of people who just want a good quality, reasonably priced -whatever- and would be fine with this model. Actually, that seems like it's basically just the business model for Kirkland.
If there was a retailer who just sold one carefully-chosen thing in each category, I think they'd do pretty well. They wouldn't be able to capitalize on market segmentation, fashion trends, etc. which would hurt their profitability, but they'd also benefit from being the "default" choice for many people.
When I am on Amazon, trying to find something, I always feel like I have to fight the site, rather than being helped by it. Paid ads, very poor categorization/property-search, deceptive UX, fake reviews, "amazon picks" etc etc etc. And when I find the right product, I might receive a fake.
I think what people enjoy and celebrate about McMaster-Carr is that it is exactly the opposite of that.
It's for people building things that already have a good idea of what they need. For the most part, if you need an 18mm long 1/4-20 flange head hex-socket grade-8 bolt in a black oxide finish, you don't care about having a ton of options from different manufacturers, because there should not be a meaningful difference between any of them.
Big retailers will have 100 different white t-shirts to choose from. Thread will (roughly) tell you which white t-shirt to buy.
The tricky bit is that fashion is _so_ personal, so what you have to do is actually have all 100 (or in many cases _far_ more), with all the necessary data to be able to differentiate, and then understand "style" in such a way that you can confidently recommend specifics. I'm biased, but I think Thread has become really very good at this.
You only compare among Monoprice, and they usually have a decent bar for quality.