Lotus Notes was too big, too self-contained, and too weird to be "Something bigger than a weird email client." One facet of being too self-contained was that it had its own user interface paradigm, which was different from the operating systems it ran on. In other words the product decisions that would've made sense in an IDE or maybe a CAD system were bad product management decisions for a groupware product. Notes also had its own self-contained application development language and runtime. That is reminiscent of 4GLs. Remember 4GLs?
Maybe there is a parallel reality where groupware is as important as web browsers, but not in this universe.
>>Maybe there is a parallel reality where groupware is as important as web browsers, but not in this universe.
Yes, it was called the 1990s.
That just feels like an extension of how things used to be done back then, especially on DOS. Making a recipe app? A bookkeeping app? A paint program? Well, you start by making a UI library first, and the product stuff got done eventually.
Then there was a transitionary period where common UIs were available, but not that great and individual shops could still easily create better experiences on their own. See eg Winamp. But eventually shared UI stacks got better and doing your own thing became a bad experience, see eg the Java UI libraries.