attrs classes still have several features that dataclasses don't, and likely never will, [like validators and converters](https://www.attrs.org/en/stable/why.html#data-classes). So it's not obsolete, particularly for anyone already relying on those features.
dataclasses have methods for iterating fields and inspecting types, so any feature can be added. There is also the benefit of type checking. My grief with dataclasses is how I can't inherit from dataclasses with default fields without making all child class fields also have defaults.