> People are talking about putting a mail order catalog store online. Presumably, sears already had the catalog, shipping infrastructure - so it really should have been about digital payments, and an online storefront. [...]

> How significant their shipping catalog was in the 1990s I do not know

Sears discontinued its general mail order catalog (which had declined in relevance for years) in 1993, the same year NCSA Mosaic was released, while the web had about 0 public penetration and no commercial use.

So, it wouldn't have been a matter of adapting the catalog business to the web, it would have been rebuilding it from scratch.

people underestimate how slow picture loading was back then. Online storefronts seem to live and die by their product images. It wasn’t really feasible to sell anything other than books until DSL came along.

It wasn’t perfect but we had plenty of successful sites where most users used dialup. You’re talking small, heavily compressed JPEGs but it was manageable and especially important to remember that people didn’t expect it to be super fast. For browsing, it was slower than paging through a full catalog but still days faster than mailing an order and less stressful for a surprising number of people than calling an order phone line, especially if they weren’t certain about what they wanted. Web pages had room for a lot more text than a printed catalog, too.

Online ordering from the paper catalog would have worked well enough to bootstrap. For items in the catalog, you don't need a lot of pictures, and they don't need to be big. If you want to have a few more pictures on a details page, you would put them behind a more photos link and show one at a time so you don't trash the connection.