FED, I agree that in practice with a normally aspirated engine running on a simple intake system, the MAP wouldn’t reach fully ambient. But depending on the restrictions to airflow in the inlet system, it can get close. Modern inlet systems include resonator boxes which act almost like “free” forced induction. Modern motorcycle and car manufacturers such as Honda have done a very good job in this respect.
An intercooler has nothing to do with protection of the turbo! It’s there to cool the inlet air temperature to the engine. This both increases charge density and reduces the chances of mixture detonation.
Having the exhaust glow red hot isn’t necessarily a problem now the days of piston engined fighters or bombers have long gone!