Indeed, when APL was first available, you couldn't use it without a custom machine: an IBM system/360 mainframe. The keyboard was the least of your worries. And

Indeed, when APL was first available, you couldn't use it without a custom machine: an IBM system/360 mainframe. The keyboard was the least of your worries. And APL was distributed for free! Why charge for software when it's written in 360 assembly? APL was near-mainstream in the 1970s thanks to time-sharing[0] (the article mentions this starting with "APL thrived in the 70's and 80's"). In fact, time-shared APL was significantly easier to use than most languages because it was used from an interactive session rather than punch cards. With results typed onto paper tape! It was used for a lot of practical tasks like administration where Excel would now be the most common tool. One book on APL had sales in the hundreds of thousands, and conferences[1] had attendance of over a thousand for a few years, despite competing with additional vendor-specific conferences. [0] https://aplwiki.com/wiki/Time-sharing https://aplwiki.com/wiki/Time-sharing [1] https://aplwiki.com/wiki/APL_conference https://aplwiki.com/wiki/APL_conference