The last time a State didn't use a vote was in the election of 1876 when Colorado was admitted as a State too late as to prepare for a vote in the Presidential election. There's no reason to think the result would've been different in that case and it's doubtful we'll see a State ever have the legislature elect the Electors save in a similar situation.
Unless the outcome of an election was in dispute and this hadn't been resolved by the time te EC was due to meet. I could imagine the Legislature then stepping in to ensure that the state wasn't prevented from casting its EVs.
This actually came close to happening in Florida in 2000.
On December 6, the GOP-controlled FL legislature convened a special session to appoint a slate of electors pledged to Bush, under the pretense that the Constitution bestows upon state legislatures the duty to determine how its state's electors are appointed. On December 12, the same day as the Supreme Court's ruling, the Florida House had already approved awarding the state's electoral votes to Bush, but the matter was moot after the Court's ruling.
Even if the Court had decided differently in
Bush v. Gore, though, the Legislature's sole stated purpose for meeting in special session was the selection of a slate of electors on December 12, should the dispute still be ongoing. So had the recount gone forward, it would've awarded those electors to Bush, based on the state-certified vote, & the likely last recourse for Gore would've been to contest the electors in the United States Congress. The electors would then only have been rejected if both GOP-controlled houses had agreed to reject them (which would've been unlikely, to say the least).
