I used to think that way too, because jio was pretty crappy at the start, which is why i kept my primary vodafone number on standby for so long, but jio is now pretty flawless in the cities. There is no reason for me to keep another sim active here, and for the villages, where jio is actually crap, i have bsnl. It's not about 35 bucks a month, i just can't be arsed to keep tabs on two sims any more...
Same here, but I moved my primary from Airtel to Jio as well (Secondary has been on Jio for quite sometime, and is flawless). However, villages are still a minor issue and especially tier 3 cities. Moving primary back in December to another operator for redundancy.