[aivisol]

>Really interesting is, that that they came there by boat, but lost the ability to build boats or stopped doing so for whatever reasons, that they could not even travel between the islands anymore.

Maybe due to lack of access to iron?

[lukan]

Possible, but there were tribes who could do sea faring only by simple wooden canoes. The polynesians for example went even so far as New Zealand by wooden boats only.

https://de.wikipedia.org/wiki/Datei:Model_of_outrigger_boat,...

And the canarian islands are really close to each other, you could probably do island hopping by clinging to some wood (but the currents and waves can be nasty there).

[aivisol]

I think as it was mentioned in the article it was mostly due to lack of need to travel: they were poor and didn’t have things to trade to justify seagoing. And then the other additional factors: lack of iron, the fact that shores were less habitable than mountains ( lack of freshwater), wind and currents between islands.

[usrusr]

Doable, but when every area that isn't up in the clouds is properly deforested at some point the economics stop making sense.