During that era, MacOS suffered from a severe lack of third-party software. This was the biggest thing keeping customers from purchasing Macs. Computers are only useful if they have software.

But lack of software wasn't an issue for websites, since Safari could, in theory, run any website as well as any Windows computer could.

While it enjoyed outsized influence, the Mac never had enough share to create a sufficiently large software ecosystem w/o the web.

In this era (~'98-'12), the web provided a bridge over a moat formed by a competitor's proprietary stack winning through momentum and network effects. The web went "over the top" of both Macs and PCs, and while Apple desperately coveted native app builders for the Mac, was at least savvy enough to know that if it could add the universe of great web apps to the Mac experience, it would be a market-reality help at point of sale.

I understand it like so: Apple computers are the luxury computers.

Up to the early 90s, most households didn't have computers; but when the Internet became mainstream from mid 90s onwards, more and more people bought computers to "use the Internet".

If Apple wouldn't have an offering/environment which allows for using the Internet (... Network stack, browser, e-mail client, dialup drivers, etc.), people would avoid buying Apple computers.

The other posts in the chain go into more detail. By improving and pushing the web experience on Mac, Apple gets access to a whole ecosystem of web-based application which make the Mac more valuable to customer, instead of relying solely on 3rd party native Mac application developers.

It's saying that small market participants benefit from open standards and compatibility. People are buying a different entry point into a massive shared resource, rather than choosing between a massive network and a niche player.