Correct. No "excuse."
But there is a reason.
The reason... and surely, I'm repeating what someone else already posted by now... is that t's highly likely that anyone you'd have chosen to compete with and potentially replace Maher was already competing in someone else's camp with someone else's 2018 kicker anyhow, and that that guy.those guys got his/their walking papers today.
It's not like kickers have to learn plays. If you decide to cut your kicker on Monday and sign someone on a Tuesday, no one worries whether the new guy will be ready for Sunday. That's now, or any other week of the season.
So, no, it's a pretty silly contention that Cowboys HQ should have used one or more of their 90 TC roster slots on a kicker to compete with Maher, when in fact, there will be ample kickers unemployed today.