Being a current Swiss resident, I rarely carry my Swiss residency permit when I travel. Twice, it's expired while I've been abroad and have picked up the new one on my return.
The reason why your Swiss Residency Permit did not matter until recently (and you you didn't carry it with you), was your UK passport.
Your UK passport granted you access to Switzerland automatically. If flying from outside the EU/UK/EEA, that UK passport was always sufficient.
Imagine you only had an Indian or Russian passport. In that case airlines would have always to see your Swiss Residency Permit.
It is just because of Coronavirus that Switzerland only allows its own citizens and lawful residents back into its country. That's where your residence permit matters again.