As everybody moves to web-based, cloud-native Saas tools, we're starting to run into the issue that browsers just aren't built for complex work in the same way MacOS/Windows are.
As you can see already in the comments here, the most savvy, HN-type users have come up with a variety of convoluted and hacky solutions to this problem already (reminiscent of that hilarious Dropbox launch comment, on Linux you can set up a system like this yourself quite trivially...).
So clearly it's a problem. Is this the right solution though? I don't know.
Some companies have created an electron wrapper for accessing multiple web apps, others have created browser extensions for existing browsers, others are building new browsers from the ground-up (Vivaldi, these guys, etc). Meanwhile incumbents are adding features, ableit extremely slowly, in this direction as well.
Browser extensions are the easiest distribution strategy, but they are going to run into feature limits pretty fast.
The electron wrapper options out there have worked for me thus far, but I have to admit I'm not loving them.
Vivaldi is interesting, but its clear to me the team working on it lacks taste and is throwing features at the wall with no real cohesive strategy.
I commend you for trying to tackle this problem on hard mode. I think the biggest problem aside from distribution will be competing with the extension marketplaces of existing browsers. If you can crack that nut, and are good at fundraising, I think you might have a chance at gaining some market-share slowly but surely.