It's not a question of "fixing" something, but of making a technological advance that makes gear changing quicker, more accurate and easier, just as indexing and integrating the gear and brake levers into one unit did. You don't need any of those improvements to use the bike just as you don't need clipless pedals, carbon fibre frames or ten sprockets on the back wheel. All these things have made bicycles better to ride, all were prohibitively expensive when they first appeared and all had the diehards howling in disbelief and derision when they were introduced, now few people would buy a bike without them.
The technology in electronic shifting is cheap as chips and prices will reflect that once R&D costs are recovered and mainstream production gets into swing. Reliability isn't an issue, cars and motorcycles are packed with far more advanced electronics and are more reliable now than they ever were. Cable systems will exist for a long time yet, but within a few years electronics will be the norm in the peleton even at club level and a common sight on cycles in general.