The reason there are no trees somewhere is never "nobody planted them". It's either "somebody cut them and does something to prevent them growing back" or "the land isn't good for trees".
So planting the trees is never the solution. Buying farming land and reserving it for forest (that will grow by itself) is much more efficient.
Do you really think that in a world where every law is rife with carve outs and loopholes for specific industries, a world where states peddle liquor and gambling because sin taxes fund things they like, that a carbon tax would not be gamed? Of course not. The societal cohesion and political process to produce results that are not highly gamed, tilted or rigged simply does not exist, or at least it doesn't exist.
Your opinion that a carbon tax will "just work" in reality as it does in theory is predicated on sufficient amounts of ignorance that the distinction between ignorance and malice is no longer meaningful.
Everything is gamed, so you try and make your incentives as simple and direct as possible.
If the goal is reducing carbon emissions, you tax carbon emissions. Any other incentive is more indirect, less efficient and more gamable.
> you just end up accomplishing nothing other than regressively taxing the entire population.
Pick one. If it accomplishes nothing, it's not an effective tax either.
Sequestration is the opposite. Plant a tree and claim 2 tons of credit, then chop it down and claim it again next year. LOL.