It sounds like the comparison with an ex-industrial city like Sheffield doesn't go that far, cities here never had the reduction in population and there aren't really many totally desolate areas. Sheffield is a relatively prosperous place now, centred around the 2 universities and the tech industry with smaller specialist steel plants still doing ok AFAIK. Whisper it quietly but maybe the EU investment into post industrial areas has really helped here
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In terms of the ownership of car companies – Landrover was owned and run from the UK, decades of under investment and poor management bought it to its knees – the ownership moved first to the Germans (BMW) then Ford (USA) and now Tata (India) and its become a world leading car brand that employs thousands of well paid, skilled workers here in the UK. So does it matter who ultimately owns manufacturing companies – its major shareholders from around the world anyway.