the irs doesnt need private keys or the seed to achieve their main objective; all the need is a list of addy you control. at that point they have all the info they need as they can then monitor those addys.

they could get those addys from ledger (trezor etc) servers now if they tried which is much easier.

all the more important to run your own full node and use that for your transactions. then only you know the addys.