IF Harris was effective in live interviews, she would be doing three a week, she isn't. Have you seen the transcript of the 60 minutes interview that was heavily edited?

She's fine. Not great, but adequate enough that she shouldn't avoid them. She needs to communicate her priorities and her vision for her Presidency, and she's not going to be able to do that without doing more press.

(BTW, people rarely look good in transcripts - one of the parts of my job I hate the most is having to read transcripts of my presentations. Real people in real life don't talk in complete sentences with transitions and predicate clauses, so transcriptions of unprepared comments always read worse than prepared speeches).

Anyway, the Democrats haven't increased taxes on billionaires for the same reason that Republicans haven't done most of the things they've promised, even when the President is a Republican - we don't have a Parliamentary government. The President doesn't just get to decide what happens. Power is divided among the branches, power within the Congress is divided between the bicameral chambers, and power in the Senate is subject to the minority party veto due to the filibuster.

So the President gets blamed for not achieving priorities that they have no power to actually achieve. It's why Trump didn't repeal Obamacare or Build the Wall the way he wanted, and why the Democrats didn't pass voting rights reform or the DREAM act or ENDA or EFCA or any of a number of priorities that they campaign on but can't pass.