I agree. It is a mixed bag though, while too many conferences might equal a lower average quality, more conferences might mean that conferences are more accessible.
More conferences also can “peer-pressure” other conferences into good behavior, e.g. a lot of conferences now provide the talks online for free. A lot of conferences have diversity or student grants. Some conferences even pay for babysitters for speakers.
Personally I don’t like the big conferences I have been to in Frontend Development. I like smaller one day events much more, higher information diversity. And I like other conferences outside of my normal scope, because I can learn much more.