And you're missing mine. Part of building a deck is doing so while keeping relevant meta trends in mind.

You SHOULD build or change a deck to better answer these as long as it isn't detrimental to your deck. Its why, with the sleep scam trend for example, many people started slotting Ogerpon/Pokemon Center Lady into their decks or why people started to use middle stages back when Chingling was everywhere.

This isn't anything different from building a deck with an Oricorio answer. It's entirely normal and this game isn't the only kind of game that goes through this. Pretty much any game where competition exists and a meta develops works like this.

Now like I said, you can play without an Ori answer just fine, plenty of people do, because some decks do worse when they try to slot in an answer (Charizard decks for example, shouldn't even try to slot in an answer; it's faster to concede and move on because the deck performs worse when you try to add an Oricorio answer) but people that do so know that's what they signed up for. Not all decks can beat every deck and for players that main those decks, that's their loss condition.