The phrase "high-quality" is doing work here. The implication I'm reading is that poor performance = low quality. However, the applications people are mentioning in this comment section as low performance (Teams, Slack, Jira, etc) all have competitors with much better performance. But if I ask a person to pick between Slack and, say, a a fast IRC client like Weechat... what do you think the average person is going to consider low-quality? It's the one with a terminal-style UI, no video chat, no webhook integrations, and no custom avatars or emojis.
Performance is a feature like everything else. Sometimes, it's a really important feature; the dominance of Internet Explorer was destroyed by Chrome largely because it was so much faster than IE when it was released, and Python devs are quickly migrating to uv/ruff due to the performance improvement. But when you start getting into the territory of "it takes Slack 5 seconds to start up instead of 10ms", you're getting into the realm where very few people care.