Was 16:9 widescreen ever used/attempted on analogue?
Yes - D/D2-MAC (which are analogue systems) had both 4:3 and 16:9 functionality (with 4:3 centre-cut for compatibility - with panning vectors) HD-MAC which carried 1250/50 HD used D/D2-MAC compatible analogue 16:9 with digital 'helper' data in blanking.
Composite Laserdiscs with 16:9 anamorphic squeeze were also released.
PAL Plus took a 16:9 source and letterboxed it to 16:9, encoding additional picture information on subcarrier at black level which allowed an improved 16:9 signal to be delivered (Higher than the 432 lines of vertical resolution you'd get with just letterbox).
The Japanese HD-MUSE compression system used in the 90s was also based around analogue video carriage on satellite.