Kazzy Investment in those areas - the wide-ranging economic and infrastructure investment needed - would be massively, massively expensive and I doubt you'd ever see self-sufficiency (the investment ceasing to be needed because the areas generate enough in corporation tax, etc.). It's been left largely to the private sector, with minimal incentives to encourage firms to set up.
Economically, the direction of travel has been to the South East for a very long time. If you were a business, would you set up where other businesses are, where you can recruit easily, etc., or somewhere where all of that is difficult?
A change of policy in this area would require a massive shift in mindset and massive funding - which is not going to be available post-Brexit.
Personally, I think I'd quite like it but ... it would require a huge level of taxation, for a start. That's why government interventions have been so ineffective, so far. There is a real unwillingness to discuss the real cost (and then the benefits) of such a policy decision being undertaken with any kind of effectiveness.
And there is also a big issue about setting up business centres in economically deprived areas. Coventry is an interesting example of this. It has managed to build quite an industry based on Higher Education and car design. It's quite a specialised centre for that - and the specialisation is part of the success. However I suspect a lot of people in Coventry possibly feel alienated by this, even colonised. Does it lead to an increase in their employment and educational opportunities? Well, yes, but very indirectly, and in ways that aren't as obvious as the influx of students from around the world, who seem privileged, and the sight of the university buying up a lot of buildings (for the education of these students).
A really imaginative approach to investment needs to be undertaken, so that people understand and want that 'regeneration' - rather than feel oppressed by it.
Mind you, I don't know why I'm even discussing it - it's so utterly unlikely to happen. Particularly on the scale that is necessary.