That’s not true at all. The aegian sea is something like 215,000 km2 (83,000 sq mi for you football field lovers out there).

And don’t underestimate “the technology of the time”.

We nowadays have evidence of wide trade networks all over Europe and northern Africa during the bronze age. In Spain there is evidence of tin being used that was mined in northern Europe. People very much used water ways for trade and exchange, which is one of the reason why most old big cities are next to water ways.