70k is enough to spend money on a 3.5 room apartment of up to 1800 CHF, eat decently with the odd meal out, go out socialising a couple of times a week, and still be comfortable enough to treat yourself to the odd purchase here and there. Fair enough you won't really save anything, but wages increase yearly so that comes with time.
Quality of life is still miles ahead what you'd get in London on an equivalent wage.