Problem: We have multiple methods of formatting text into columns. Most of these methods break on mobile displays. Some of them break for desktop displays (it looks good on my screen, but not yours). Several of them get mis-used and produce invalid HTML. If you aren't at a wiki that has imported or created those templates (or if you can't find them), then your choice is to add the HTML codes directly or live without columns.

Proposal: Let's actually do this right. Instead of adding complicated HTML or a series of templates that inserts various bits of HTML, let's do this in wikitext, with a simple wikitext-style code like "[|" to start columns and "|]" to end it. (This suggestion mirrors table syntax, so remembering it would be easy for experienced editors.) Give it some sensible default that works for most cases, like a 30em minimum width and a maximum of three columns, and (probably/eventually) let people change it.

Related discussion: https://en.wikipedia.org/w/index.php?oldid=655461344#Columns