Firstly, middle managers do not generally set wages. Secondly, plucky little startups with limited cashflow do not provide the bulk of employment in the UK: that would be enormous companies with more than enough money to pay their employees substantially better.
Paying employees the "bare minimum" is a scummy and unnecessary business practice, and you cannot complain about wage depreciation while defending it.
Wages are, in theory, the result of a negotiation between employer and employee, in which both have leverage. Except both do not have equal leverage: the employer has an immense amount more power, as well as the deciding vote. The employer has more than enough money, and can decide to do whatever they want; the employee, on the other hand, often has little choice but to accept whatever terms are on offer, because they desperately need the money to be able to pay the bills and keep the lights on.
In blaming the employee, you're blaming the one who has the least power in the negotiation. In absolving the employer, you're absolving the person who had almost all the power in the negotiation, and the one who actually made the decision.
Employers can take responsibility for their own damn decisions. They're the ones setting the wages, and 9 times out of 10 it's not out of necessity, but sheer profit. They can take goddamn responsibility for their own choices.
The minimum wage, and collective bargaining (via unionisation). Both of which have been relentlessly undermined by the Conservatives.