This topic came up talking with relatives over Christmas and I couldn't figure it out.

This topic came up talking with relatives over Christmas and I couldn't figure it out. Maybe the Fediverse knows

1. There was an era in the past where if anyone posted a vertical video they would be teased, mocked, ridiculed

2. Today, the status quo, every video is vertical orientation and no one even remotely considers it strange

Roughly when did this happen?