He was half a second behind Vettel with DRS and a faster car. So how exactly were other drivers able to pass other cars on the track? Your 'it's impossible to pass there' argument does not sound reasonable. Also, if he had not gone off track due to a mental lapse, he very well could have passed him.
Who overtook who? Bottas on force indias, the slower mclaren, ricciardo on renault, verstappen on renault, that's it, no?
Did you see any of the top 3 teams overtaking each other?
I'm talking about fairly even cars, mercedes, ferrari and red bull, that it was hard to overtake has been shown also by all the complaints from drivers, and who said impossible to overtake? Not me, I said impossible to overtake a slightly slower car, like a ferrari was for a merc.
Hamilton couldn't have passed vettel even in the whole 58 laps, just like verstappen couldn't pass alonso for all the stint after the safety car and just like ricciardo couldn't pass raikkonen.
The reason FEW overtakes took place is cause the performance difference was like 1-2,5 sec depending on which car, not half a sec!
https://www.racefans.net/2018/03/26/f1-drivers-say-overtaking-even-harder-year/
Drivers, including hamilton, complaining about how hard it is to overtake.