People who are doing useful/meaningful/important work that benefit the mankind & society have not being paid commensurately

It seem that in the past >10 years, some very unhealthy development has been happening in Singapore, and in many parts of the world.  The development is that:
          "People who are doing useful/meaningful/important work that benefit the mankind & society have not being paid commensurately!"

We are seeing these development when we see that engineers who are doing jobs to repair and maintain the aeroplanes, the MRTs, the buses, developing products that will save life or to help people to have better life etc are being paid a salary that have not increased as much as inflation over the past many years, while people who are doing what we would regard as "useless" jobs are racking in huge incomes, like traders, "pushed" salesmen (trying to sell things to force us to buy when we don't really want or need), and people trying to persuade others to join their MLM companies, and the many middle managers and administrators (don't know have so many layers of "managers" for what?)

E.g., a corporate commodities trader, their job is to hedge against the company's physical commodity prices, yet I heard (from a friend working in commodity firm) that many such traders are really engaged in speculation rather than hedging.

Then there are the "pushed" salesmen getting a big cut of commission when their service are not really needed, like the insurance agents (like "salesmen") selling insurance in Singapore.  This has come to such bad shape that MAS, Singapore Monetary Authority of Singapore (the equivalent of Central Bank in other countries), having to step in and dictate by law that insurance companies must have direct sales channel to their potential customers to cut out these insurance salesmen who are not needed (if these people do not require the insurance agents advise).  I abstract part of the news article as below:
"
People in Singapore will be able to buy certain types of life insurance products directly from insurance companies starting next year, saving on commissions. This is according to the Monetary Authority of Singapore (MAS), which said on Wednesday (July 30) that all insurance companies that serve the retail market will have to offer the following direct purchase products:
(a) Term life insurance products with Total Permanent Disability (TPD) cover;
(b) Whole life insurance products with TPD cover; and
(c) Optional critical illness (CI) rider attached to term life or whole life insurance products.

Consumers who wish to buy direct purchase products will still be subject to underwriting by the insurer, MAS said. "When direct purchase products are introduced in early 2015, they will provide consumers who do not require advice with cheaper access to selected life insurance products," Mr Lee Boon Ngiap, Assistant Managing Director for Capital Markets at MAS, said in a statement. "Consumers will benefit from the greater price competition that will be introduced between the direct and commission-based channels." 
"

Remember the SMRT trains keep breaking down saga?  Why would the trains keep breaking down or keep getting delayed etc? One of the main reason (I heard) was that the engineers in SMRT had previously been treated as people who only “costs” SMRT money, since they only incur costs by maintaining the trains and tracks and equipments etc BUT do not help to bring in REVENUE! As such, they have been treated badly so much so that many knowledgeable, experience and skilful engineers left, which then led to SMRT trains keep breaking down etc while the remaining engineers (who are not as experience, knowledgeable and skilful) are unable to resolve the problems!

Things have become so bad that after that we read on the news such as:
“Government to hire 1,000 engineers this year”… “It will review salaries to match market rates, provide training and leadership grooming”

“Singapore needs more engineers, less short-term planning”

“New rail transformation advisor named amid 'serious refocus' on engineering”

“Engineering focus needed to help get Singapore's tech talent to return home, says PM Lee”

“S'pore 'must value engineers the way Silicon Valley does'”

However, the most important question the Government and companies (especially Government Statutory Boards and GLCs) have to ask themselves is this:
If you can’t even keep your existing tech talent (like those of SMRT knowledgeable and experienced engineers), then what makes you think you can persuade tech talent currently living and working overseas to come back to Singapore?