What retailers offer is totally spotty. Marvin, Kohler and Kraftmaid have good stuff in 3D Warehouse, but most are nonexistent. I just posted and example of where I had to make my own model of a Home Depot product from online info in this thread. It costs time to make them.
I can’t recall ever seeing a retailer have any kind of downloadable models - except (perhaps) McMaster Carr. Models, when done, are usually done by the manufacturer who makes them, not the retailer that sells them.
As others have said - SOME manufacturers have CAD files available in different forms on their company site - in various forms. If a .skp file is NOT available, but other are, look for a file TYPE that can be directly imported into Sketchup.
Fewer manufacturers have populated the 3dWarehouse with their product .skp files. And many who do have made available models that are “heavy” - showing things in incredible detail with high edge and face counts - FAR higher than are needed in MOST SketchUp project models.
Interestingly, home decor retailers in Brazil share LOTS of models through 3D Warehouse. If you do a search for “mobiliário” or “móveis” you’ll get an idea of how many shops participate.
That being said, we are currently looking at better ways to meet your request, Tsquared1994. Feel free to reach out to me directly if you’d like to tell us more about what you’d like to accomplish.