The 3290 was like a 4 split tmux session, it is such a beautiful device (https://ifdesign.com/en/winner-ranking/project/ibm-3290-info...). Perfect keyboard, plasma contrast and the right text color for long sessions. My understanding is they outlived themselves with long service in air traffic control (supplementing vector/raster displays), financial markets, and software development. Once upon a time people seemed to really care about doing things well.
Years later, probably around 2003, when desktop apps started getting replaced by web apps (at least at my job), I remember making that connection between web browsers and 3270s. In the 1990s, clients got very fat (think powerbuilder), but then in the late 1990s and early 2000s much of the fat went to the server-side and the web browser became the thin(ish) client. The web browser was sort of acting as a block device (like the 3270) in the sense that the end-user filled data into fields and then sent the whole thing at once by hitting some button.
With Web 2.0, the client started to put on weight again. Then with mobile apps, the fat client was back, baby! It just keeps cycling.