I used to use a tiling wm but now that everything supports dragging windows into a side of the screen to make them take up half the screen, I find that my main usecase of tiling wm's: side-by-side windows, is handled well enough that I don't want to put up with the occasional annoyances.

The main pain point of stock ubuntu gnome for me right now is that when I open too many windows, my alt-tab becomes too cluttered, and it would be cool if there was a way to designate windows as background somehow (but not different workspace, I don't like workspaces), so that it would not show up in alt-tab. Ideally I would be able to have like 40 open windows of which just a handful are "active".

EDIT: The side bar could be used for bringing up windows if it didn't combine windows from the same program into one icon - a feature I absolutely loathe - seriously, I have a lot of empty screen real estate but instead you want to hide my windows behind a second click?

I can answer you from my perspective. I used i3 and also awesome for some time but they didn't give me real benefits. Instead they made the occasional floating window look and work crappy.

I use byobu(tmux) for managing my terminal splits, which is all i need. I also have removed any window decorations from my terminal. I have shortcuts configured in gnome which let me do the occasional side-by-side windows easily. I rarely use the mouse but I have the option.

Of course if you do a lot of crazy tiling like 3,3,2 or whatever, a tiling window manager might be a good idea. In my experience you just never need that. Maybe I am missing something.

Because it doesn't really boost my productivity. I try to keep the number of windows opened to the minimum: Having more than 4 windows opened is counterproductive (at least for me) since it implies 4 different context I must switch between. I can handle 4 different windows opened easily without any tiling wms.

The windows I have opened are: - the terminal (at most 4 tabs as well... but here my terminal allows me to easily switch to any numbered tab I want) - the IDE (sometimes). In most cases, my IDE can be run on my terminal (e.g., Vim) - a web browser (again, I try to keep the number of tabs to a minimum... but here it's harder to do so) - anything else (usually nothing)

Another reason to not use a tiling wms: yet another dependency I don't have to take care (as in: configuring and updating it).

Despite trying many times and many different tiling wms, it doesn't solve any problem I'm having. Basically every window manager (and Windows) lets me easily put two windows side by side in different ways and have multi desktops. Beyond that my editors, IDEs, and terminals support both tiling and tabs "internally". Between all of that all my tiling needs are more than met.

I think it's because most tiling WMs have a really steep learning curve, often not even providing basic things like window title bars or automatic lock/suspend, expecting the users to configure all that to their liking. Perhaps some sort of a gateway drug is needed, something can help introduce people to tiling while also providing good defaults and the usual desktop environment comforts (title bars with buttons, lock/suspend, volume and networking controls, a proper settings app, etc).

I used i3 for a 4+ years, then a few months ago I got tired of the screen tearing when I scrolled in Chrome and the screen showing a frame or two of checkerboard patterns (actually it's more complicated, like black pixel fuzz around text that used to be there) any time I resized or moved a window. Now I just use the built-in Ubuntu desktop environment (tried the Wayland version but Spotify and Discord don't work). Since most of the time I just have a terminal, Chrome or Emacs in full screen it doesn't even matter.

Starting compton (which seems essential for i3 but the documentation doesn't mention it) didn't help. Enabling some Intel drivers fixed the screen tearing but broke my multimonitor setup.

Also dmenu is garbage compared to program search in modern desktop environments, it's just search for bash commands, half the results arent something you'd want to run from your desktop and it doesn't learn.

It makes sense that it's not popular, most people have better things to do than read a manual and learn a new configuration language with 100s of options just to move windows around.

From what I observer, they first give it a shot, but dont utilize multiple workspaces and give up

Because they don't know how to computer

They do. Most IDEs behave like tiling WMs.