Railway systems in other countries use In-cab signalling on their trains that keeps the LP updated on the upcoming signals ( England still relies heavily on track-side signalling like IR and has similar issues). IR tried in-cab signalling several times in the past, most notably on the HWH-MGS sector. The initial attempts failed as the track-side magnets required for the signalling were subject to theft.
A bigger problem was the encroachment of people/live stock etc on the tracks which cannot be handled even with in-cab signalling. This is a new problem even for outside manufacturers. That's why it's taking a lot of time to hone in on a solution.
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more... That and IR's general laziness in upgrading it's locomotive fleet with new features.