Up to my best knowledge, the idiom "smth is built to last" means that smth is durable, of high quality and expected to serve for a long time. However, I cannot understand what does the phrase mean literally. I have two guesses.
The first one: "last" is a verb. The builder expects that smth will last (continue its being) for a long time.
The second: "last" is an adjective. Like "built to the very last age". It doesn't look like a grammatically correct sentence to my intuition, though many English idioms do not as well.
Which is correct?