negative interest rates is one thing, transaction fees are the next
Yup. Negative rates don't work well if people can convert to cash or cash like things. I'm not convinced transaction fees are next, but they're probably on the table somewhere. What the government really want to do is eliminate tax dodging by working or paying cash in hand; unfortunately that makes everyone's transactions traceable thus eliminating privacy.
Without cash there is no escape, except: moving savings to another country, another currency, gold, silver.
Another country & currency exposes you to FX & political risk in the new country. Unfortunately it's not a free ride, though I suspect a lot of people would go that route.
Gold & silver don't work well either due to the bid:offer spread available on in hand commodities, rather than those held within a vault.
I simply don't have a better answer however, because I don't think there is one available yet. I do expect someone would find a way to workable solution to the problem, but I don't think it's going to be any of the above.