I'm sure electronic shifting already is cheaper to manufacture. Just a question of marketing as to what level they sell it for.
So it will soon trickle down to the cheaper groupsets. And probably some cheap Chinese copies, which could be compatible with the Shimano stuff.
Absolutely.
It is usually easier to predict the long term future than the road by which we get there - and less risk of being proven wrong any time soon!
In 10-15 years time:
- Gears will be like watches. Virtually every bike will have electronic gears, mainly because it is cheaper but also a bit better for most people as well. There might be might be some high end mechanical systems for particular niches such as retro
- Shifters will be cheaper than they are now. Most relevant patents will have expired (that is what stops copies of Di2, etc, not engineering challenges) so there will be low-cost options.
The challenges for Shimano et al are:
- to delay the inevitable as long as they can
- invent more new stuff to justify/support premium pricing
- manage the lifecycle of Di2 to maximise their profits
Basically the same challenges that companies which design and manufacture things have always faced.
So they will try to keep electronic priced at a premium to mechanical as long as they can. The main purpose of high-end mechanical at this point is probably not to make money (hence no investment in it and few people buy it) but to support the price of electronic - to give it something to be premium to.
They will also try to patent all sorts of different things to defend Di2 as long as possible - but it won't work. At some point the dam will break and good alternatives will be available for surprisingly little money. Archer is something like $300 for rear-only, but they are not manufacturing at scale. Maybe it will be more like £100 for front and rear shifters within 5 years.
This will be great for the utility market but Shimano and the others will make sure that there are some things that it cannot do so that it is not great for high end. And the fashion gatekeepers will hate it!