I am not a metallurgist but surely there is another cheaper metal that can do the job other than silver?
Nope. We use gold & other precious metals in electronics and other applications because we have to, if there were a cheaper way we'd be doing it already. The alternative will give a brand new meaning to "planned obsolescence" and "limited shelf life". As in your electronics are DOA or soon thereafter, assuming they could be built in the first place since no other metal can be drawn as thinly as gold and without those microscopic gold wires there are certain chips which can't be built.
As for why gold is going up & away, well, it is, but it isn't. Priced in US dollars it's going through the roof, price it in Euros
and it's been flat for the last couple months. It's more a symptom of a falling USD than anything else, the USD is going splat thanks to central bank & economic policies so everyone piles into precious metals & commodities, and the price zooms upwards until there's no more buyers. Then you get an kaboom, and what happens then & after isn't going to be pretty.