What if Columbus reaches the Americas had gone differently?

A Castilian expedition makes landfall in the Caribbean, opening sustained contact between hemispheres.

If it had gone differently: The Atlantic stays a barrier for generations; Europe's empires grow east, not west.

1. 1500The Columbian Exchange, No potatoes or maize in the Old World; European populations stay smaller and hungrier.
2. 1525The Atlantic slave trade scales up, The plantation economy never finds its labour force; Atlantic colonies stay marginal.
3. 1600The chartered East India companies, European trade with Asia stays a matter of small merchant convoys; no company-states, no gunboat empires.