Basically, the SAR-80 design was deemed obsolete in the
international market, given the technological developments of the
industry.
To start, you must separate the weapon maker (CIS, now known as ST
Kinetics) from the supposed buyer (SAF). CIS began as an authorized
armament manufacturer, producing M-16s for our army & also for
export. It then lost the licence to continue the latter, &
attempted to develop its own rifle modelled after the rival AR-18
rifle.
The AR-18 rifle was supposed to compete with the M-16 back in the
'60s (when both sought to succeed the M-14). The M-16 proved more
popular, but - wisely or not - the then-fledging CIS chose to hire
foreign AR-18 engineers for what turned out to be the SAR-80.
They finalized the prototype around the time I enlisted in the
mid-'80s - I think I saw it on display during the Army Open House
then. The SAF bought some, but apparently never distributed it to
the line units. They then passed on ordering CIS's attempt at an
improved AR-18 model (the SR88A), in favor of the Ultimax 100 (as
the new SAW for the army).
Even as CIS moved on to develop the SAR-21, it doesn't mean the
SAR-80 or SR88A have disappeared. Since they're known as "cheap
AR-18's", they are making the rounds among mercenaries.