This is not the first campaign to limit immigration. Switzerland is attractive with high immigration due to big companies (Nestle, Roche, Novartis, UBS) needing workforce. Right-wing forces campaigned for decades to cap immigration/population, arguing limited space. Companies resisted, saying it cuts off vital immigration. Voters voted with their heads, dodging a bullet as economists said it wouldn't work. Good for Swiss economy.
The right-wing Swiss People's Party was the main proponent. The proposal was a vehicle to appeal to middle voters.