The free modelers, NAM and Proteus, suffer from tying a player to a computer, either laptop or desktop. Kemper was always about freeing you to take a box (toaster/rack) or a floorboard to gigs with your sounds inside for use. What the freebies have not done, nor are likely to do, is offer that portable hardware to rival Kemper, at least not for free.
That currently leaves Axe-FX, Kemper, Quad Cortex, or ToneX. Given the recent flush of new hardware based systems, could we see 5-7 more within three years?? What a time to be a geetar player!!