With great civilizations coming up in the Eastern Mediterranean, Along North Africa, in Greece, and the Italian Peninsula why was there no indigenous Classical Empire in today's Spain and Portugal, rather than just colonies of Carthage and Rome?
Well there was Tartessos. It was a trading power in the southern tip of Spain.
Which was one of the nations that had interactions and rivalry in Stirling's ISOT series. Right?
I think he meant just any city/state in Iberia forging some sizeable and powerful state. Kind of like Carthage.Tartessos wasn't per se Iberian. Actually, the few things we know about them were they were really distinct of their neighbors. It probably developed according the economical and commercial development on western Mediterranean basin.
That's one of the issue : Iberian covers many situations, cultural, political, economical. It's a comfortable name that Greeks gave to the inhabitants of eastern part of the peninsula, then to everything not Greek or Phoenician in this same peninsula. More or less like they named Ligurians peoples living in the mediterranean shores without caring too much if they were related.
Then, you need to have Iberic peoples to be more than tribal states or confederations, and more of develloped city-states.
The issue is that appeared in Spain and Gaul mostly because of Greek presence that influenced culturally, politically, urban life, etc. the surrounding populations.
Now, OTL, you had progression of Iberian settlement and economical influences : in mediterranean oppida of southern Gaul, the iberian presence is well attested even if it's more of a Celto-Iberian one as it was mainly the case in S-W Gaul.