Re-: the problem of access to the water for seals and people.

Wikipedia – last glacial period

The Arctic Ocean between the huge ice sheets of America and Eurasia was not frozen throughout but like today was probably only covered by relatively shallow ice.

If true, this still leaves the biggest hurdle:

comment 48 by Jonathan Dore

the psychology of spending years or even lifetimes out of sight of land……

Two thoughts on this, very much off the top of my head.

1) The motivation was fear of the tribe who pushed them off their former territory. In the repeated tellings of the tale of their exile, their conquerors mutated into man eating monsters. Their tribal lore became "trouble comes from the East: always head west" They stumbled upon America, where some millennia later, the Clovis people arrived from the West and ate them.

2) They were led by a psychotic patriarch, who heard voices telling him to lead his people out onto the ice desert and then they would find their promised land.

I realise that these are both highly unlikely, but somehow the "French" flint did arrive "Stateside"

I think that I understand Helga's comment 42: "the stuff got traded a long way" But if it didn't travel along the coast, it means putting people up on the ice miles above sea level where, as I understand it, there'd have only been lichen and beetles.