Well, here we are making rollerblades again.

In fact there is a Australian contraption for downhill boots that use
4 wheels as well - sort of rollerski for downhillers. So Jenex is not
alone.

The problem is still the same - darn things are just too fast and roll
too easy,
especially on rough pavement.
Outfitting it with 80mm rubber wheels (K2 Speedgrip) should make it
slower and grip even better.