"we will be leaving after those trade talks - if those trade talks fail, with no deal"?
I guess the argument would be that they are just triangulating to bring the "awkward squad" onside, after which of course they will strain every sinew to achieve a trade deal. This isn't beyond the bounds of possibility. Though there isn't a snowball's chance in hell a trade deal can be concluded in 14 months. We get another pinch point at the end of 2020 and the outcome likely depends on Parliamentary arithmetic at the time. If there is a big influx of hardline Brexiteers at the next election, it's not hard to imagine which way the wind will be blowing.
I suppose it comes down to how trustworthy you think Gove, Raab and Johnson are. I've got a very firm opinion on that, personally.