I think you are externalising blame. The blame plainly sits with the business management.
35 or 40 hours is really irrelevant, unless you are the employee.
The problem comes down to the fact that most humans are rubbish at what they do or don't care, businesses look at short term cash flow rather than long term investment or the business isn't viable to start with. The typical failure scenarios are:
1. They hire the cheapest people who will do the work then whinge when they have to hire two people to cover that time because the first person is inefficient, incompetent or disinterested in it.
2. They hire humans rather than make a long term investment in automation or subcontracting services out.
3. The business isn't really viable. So costs are cut and the business scrapes along.
Do you understand that the large youth unemployment many countries face is because of such policies you applaud?
The large youth unemployment is due purely due to the fact that the governments support people who don't aim to work in society. They are not employable, apart from by businesses described in case (1) above at which point they self-perpetuate the failure mode.
Businesses need to stop blaming everyone else for their own failings and start looking in the mirror. If a business is failing, then it's mismanaged, isn't hiring the right people or is not viable. Not all businesses can be successful.
For ref, I've built and sold three SME businesses. I now work for another one as a major stakeholder.