When you purchase a "carbon offset," you are paying someone not to emit carbon that they otherwise would have emitted. You're not getting rid of any actual emissions.

The current marginal cost of offsets is $50/person/year because nobody buys them. But if we all paid each other not to emit any carbon, what would the cars run on? Certainly you couldn't pay a person $50/year to stop using any transportation or power.

Offsets are a dead end.