So is Missouri going to vote to the right of Kansas?
More likely with every passing election. If it doesn't happen this year, it will in 2022 (especially if Galloway somehow manages to win).
Is it just that suburbanites are a bigger share of the population in KS than in MO?
Yes. Particularly notable is the 15-point swing of Johnson County, KS from 2012 to 2016. Romney +17 to Trump +2.
That + Democrats have been almost completely shut out of rural Missouri, particularly since 2014.
This is what a Missouri Dem maxout looked like in 2008 (Nixon +21 for governor):
And this is what it looked like ten years later (Galloway +6 for state auditor):