If it is the client's fault for the mistake, make them wait until it is ready.

As for why it is late, the IRS has DRAFT instructions for 2018, but those Instructions are not Final yet.  Intuit rarely does any programming without Finalized Forms and Instructions.  So I suspect the main reason for the delay is because of the IRS's delayed final Instructions, not because of Intuit.

EDIT:  The IRS has now finalized the Instructions (on February 22nd), so it is likely that Intuit will finalize their things within a couple of weeks or so.