alt Hacker News> The downsides of idle stops are, however, that they tend to put a lot of load on the engine
While I don't doubt that it seems like this is essentially a solved issue. Priuses are some of the most reliable, long-lasting cars out there despite experiencing considerably more start-stop cycles than a traditional ICE with start-stop would.
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A Prius isn't taking off from a stop under strictly ICE power. The electric motor in the transmission lowers the load on the ICE, certainly enough to let the engine oil pump generate operating pressure before it's really under load.
Up to 2022 the Prius' ICE barely had 70 kW of engine power, and (IIRC, take with a grain of salt) neither turbochargers nor compressors. The less capacity the engine has, the more abuse it can tolerate, and it likely was ridiculously overspecced in tolerances and thicknesses.
In contrast, your 100 kW+ average vehicle? Probably built for maximum profit margins.
Hybrids likely have more engineering around the start-stop cycles than full ICEs with start-stop bolted on to meet emissions requirements.
The prius style dual motor/generator planetary gear arangment avoids concerns about starter motor longevity. But the engines and how they're managed is tuned for their use case.
I'm sure ICE with start-stop will get there eventually, but the automotive industry tends to learn to build reliable drivetrains through a history of failure. From my experience with a couple rental cars a year, on user experience, start-stop is all over the map from really annoying to noticable but unobtrusive ... I imagine how design challenges around lubrication are met is also all over the map.