I think we might have different definitions of competition. As of July 2020, Discord had over 100-million monthly users. At last count, netsplit.de reports 360k IRC "users". That's not even 1% of the Discord user base and it's shrinking every year. No new significant IRC communities have emerged in at least a decade because it's a dying protocol while Discord adds millions of users every month. Yes, IRC is an alternative to Discord but it's not a competitor (to Discord, or any other protocol) by any stretch of the imagination.