Mexico has been doing that since the 90s, with the PREP (Programa de Resultados Electorales Preliminares). Preliminary results start pouring almost soon as the voting period ends, and in 24 hours we know the winner. Statistical models are perfect for this scenario, as they become increasingly certain. In my country, the loser has conceded defeat before all 100% votes are counted, by sheer mathematical certainty.

It always surprises me that USA, the self-appointed bastion of democracy worldwide, has such tortuous and malleable elections; and that no serious academic discussion occurs despite the endemic flaws. Even these days, the PREP's Wikipedia page lacks an English translation.

https://es.wikipedia.org/wiki/Programa_de_Resultados_Elector...