I cannot speak to Phoenician architecture, but I can definitely make a point about survivorship bias, especially in the context of Carthage, by touching on a few points

First, as Rome’s first real overseas territories, most of the Carthaginian Empire fell into Roman hands and remained Roman largely until the fall of the West. As this encompasses 600+ years, even where the cities were not destroyed and replaced they would have been subject to the gradual romanization process that introduced quintessential Roman architecture to the region (I.e villas, which were especially important in Africa). The city of Carthage was rebuilt on (or nearby?) the site of the city, and became an important site for Roman architecture.

Additionally, Sardinia provides us with another reason why Carthaginian cities might have been lost to time: economic reorientation. Up until it was annexed by Rome, Sardinia’s “centre of gravity” so to speak faced southwards directly to Tunisia, exemplified by size of the city of Karaly (Cagliari). However, once it became Roman and an important production area for grain, other cities like Olbia (facing Italy) expanded in importance. This is not to suggest that people stopped living in Carthaginian cities, just that the Roman state enabled significant economic migration, with one figure during the imperial era putting the percentage of the Roman population not in their region of birth at 40% (similar to the modern United States).

Finally we have Roman colonies. While the meaning and purpose of these colonies changed significantly as the empire continued, most of the colonies established in the domains of the Carthaginian “empire” would have served a similar purpose to the “garrison” colonies of Latium and Italy. As the Roman republic did not yet possess a standing army (though it shortly would) placing sizeable groups of Romans directly into newly conquered cities aided both in the romanization and in keeping its populace loyal. However, most of these colonies (though not all) were carved directly out of existing cities, meaning that Roman colonists generally received prime urban real estate. These colonies would often serve as “ground zero” for Roman architecture, which local notables could then work to imitate, gradually transforming the architectural landscape.

Finally, as an empire, much of the land Carthage controlled wasn’t strictly “Carthaginian”. While colonies were always established, much of the hinterland remained indigenous. As a result, the map can be deceiving, because the actual spread of Carthaginian architecture and urban areas would have been much smaller and less extensive than the entire western coast of North Africa and about half of Iberia.

Part of this, besides the other excellent answers in this thread, has to do with the history of archaeology. A lot of those grand temples that we think of when someone says "Greek architecture" weren't found intact. They were rebuilt. Not all of them, for sure, but especially in Turkey and the Near East, many of the really spectacular tourism sites are reconstructed at least to some extent, especially if you see standing pillars. That architecture, along with "treasures" like gold and art, was also the goal of archaeolgy in the 18th and 19th centuries. Europeans wanted to restore the glories of the past as part of their project of situating their own imperialism in the lineage of Rome and Greece. It wasn't so much about scientific and historical inquiry.

It's become a problem for people wanting to study periods outside of the classical and Hellenistic, because a lot of evidence for the middle ages and late antiquity was destroyed to get to the classical and early empire stuff, and once that stuff is found and made attractive to tourists, you can't just destroy it to get to the older layers. There are much better, more scientific methods now, but in many cases the damage is done. Not to mention areas that are still inhabited.