I'm not sure "I'm not a monopoly, look my competitor owns 2% of the market" is an effective defense anyway? I think only Safari really counts as a "competitor"

I'm not sure "I'm not a monopoly, look my competitor owns 2% of the market" is an effective defense anyway? I think only Safari really counts as a "competitor" at 20% market share and doesn't share the chromium base (compared to edge, etc).