People could never have imagined getting together for drinks online 50 years ago.
People would have never thought to have a few drinks with other people online 50 years ago.
この場合、次のように言うと良いですよ!
ーPeople could never have imagined getting together for drinks online 50 years ago.
「50年前はオンライン飲み会なんて想像もできなかった」
could never have imagined で「想像もできなかった」
to get together for drinks online で「オンラインで飲みに集まる」=「オンライン飲み会をする」
ーPeople would have never thought to have a few drinks with other people online 50 years ago.
「50年前はオンラインで飲み会をするなんて思いもしなかった」
would have never thought で「思いもしなかった」
to have a few drinks with other people online で「オンラインで他の人たちとお酒を飲む」=「オンライン飲み会をする」
ご参考まで!