For the Labour Party to win outright they need no only to be broadchurch of socialists and social democrats, but also form alliances with Nationalists, Greens and even Liberals.
A pure socialist party would never win over 300 seats in this country - in 2017 a high water mark for Labour recently it was 262 seats. The World has changed since 1945, ordinary people own houses, they have other assets like private pensions, investments. People with modest ownership of assets need to be feel protected from tax rises. Labour would need to win Redcar, Hartlepool, Middlesbrough SE, Stockton South - none of those seats are affluent areas overall on National scale.
If you don't own your own home and have very limited assets or have a income below £25k it easier to vote for Labour.
Look at Simon Clarke's constinuency (Middlesbrough SE), there are a lot of homeowners (Saltburn, Loftus, Guisborough, Marton, Ormesby), probably around 80%. Over 70% will be basic tax payers, probably 20% non tax payer and 10% higher tax payers. A lot will have private pensions or building up a private pension. There is a definite segment (of over 65s) that worked for ICI for 25 years or more and have a decent ICI pension. In 1945 it would have been 25% house owners and only 50% would have paid income tax. Today the continuency is not wealthy, but he has a big Tory majority. My guess is incomes are 10% below the National average, wealth is 30% below national average. Brexit has been good for him, but the seat should not be Conservative.
A Blairite approach work is Middlesbrough SE, modest increase in public spending particularly in schools and NHS, paid by higher income tax payers. It needs all the levelling up agenda that the Labour Party has allowed the Tories to take ownership of, particularly on economic and industrial issues.