Some did (the Spanish church from the example I gave named their first pope after the death of Paul VI in 1976), but nothing stops you from having your own conclave of bishops, and have them say that the current Pope has been judged inept to rule (although that has never happened before in the Holy See).
Which would make the line unbroken, the same way that the line was still unbroken when Benedict XVI resigned and Francis was elected pope.
I mean, there are already plenty, for example, Peter III, who leads a Spanish church that believes they are the rightful Church. (Also, antipope is a subjective word, like heretic. From the perspective of various sects, the Pope Francis is the antipope.)
Nothing stops you from calling yourself Pope and claiming you’re the rightful leader of the Church, hereby making you an antipope to the eyes of the Church.
Now is there going to be a relevant antipope, that’s a lot less likely.
The relevancy of antipopes hinged on the political power of the pope. Having the pope at your beck and call was an extremely powerful tool in the Middle Ages. But nowadays, between the secularization of most Catholic countries, and the massive loss of influence of the Catholic Church, an antipope would only have as much influence as his followers would give him, especially since they wouldn’t have the support of the Holy See or the Church.
He was also Director Trench in Control.
RIP
Join the neolib orgy with Reagan and Pinochet.
Even Satan is turning his eyes away from that.
And then there’s Pluto, by Naoki Urasawa, which is what would happen if Philip K. Dick decided to write an Astro Boy story.
(It’s a reinterpretation of “The Greatest Robot on Earth”, and was supervised by Tezuka’s son, 100% worth a read)
For the Pope to turn into an antipope, you’d either need to have a massive schism in the Church that leaves the current pope completely stranded politically and causes the Church to ignore him, or you’d somehow need a higher authority than the Church to show up and name a different pope, and assume the current one wouldn’t yield.
So basically, short of Jesus showing up and naming a new pope that the current one doesn’t agree with, the current pope won’t become an antipope.