 Di Maio is not that unlikely, the possibility that he (or for that matter, anyone else from the movement) actually becomes prime minister is rather thin. This would be a risky proposition to accept without a true majority. As things stand at the moment, Grillo would most likely reject the offer. He would consider the compromise with the establishment a strategic mistake, as he did in 2013 when he turned down the offer from Pierluigi Bersani, then Democratic Party secretary, who was in desperate need of an ally to govern.
If a temporary solution cannot be found and an election is called, under the current electoral law, the election might lead to political bloodshed. In a climate of widespread discontent with the country’s political establishment, the new law and its proportional mechanism that gives the winner an automatic majority in parliament, most of the parties in the current government coalition might be erased from the electoral map. Though that might provide some sweet schadenfreude to many disgruntled voters, it might eventually cost Italy dearly.
The ultimate winners of the coming electoral melee are likely to be untested populist forces with a strong anti-European sentiment and some more questionable political ideas. When something similar last happened, Italy ended up with two decades of Berlusconi. The ride was far from fun and the bruises are still there for everyone to see.