No one will argue with you if you tell them that they should invest their passive income (savings) in a variety of ways. Some in stocks, some in bonds, some in real estate, and some in a secure savings account. This way, if the stock market crashes, the person may lose a lot of their money, but at
least will not lose everything. They can still pick up the pieces and go on with their life.
So it surprises me that when it comes to active income (your job), our society encourages; in fact, practically insists, that each person hold only one job. I would venture that over 90% of Americans find themselves in employment situations where, if their company crashes or they get laid off, they will be completely incomeless.
This is an insecure system. It puts extraordinary financial strain on the government to provide unemployment insurance for the Americans (I assume this happens in many other countries, too) who find themselves out of a job. It also leads to job lock, where workers find themselves stuck in one job because they are not trained to do anything else, or because their health insurance policy is not portable from their job to any other job. Anxiety over the possible loss of their job, plus boredom and dissatisfaction should it be a job they dislike, become dominant in the American workplace.
Almost all Americans are capable of performing more than one job. They just haven't been trained to do so. I propose that a two-job employment system be created. A full-time secretary could get a second secretarial job at a different company, and hereafter work at one company Thursday and Friday, and at the other company Monday through Wednesday. In fact, cross training is even more secure. The secretary could take a proofreading class and work in publishing Thursday and Friday, and at his/her secretarial job Monday through Wednesday.
Entrepreneurial types will want to create a product or book or seminar program on the side to make extra income that way; this should be encouraged by our government and society, not shunned as disloyal to one's employer. Because the entrepreneur in this example will not find himself homeless should his company go under, the government or the company should encourage his side passion by, for example, granting him extra days off from work to pursue it. (To avoid "malingering", the employee should be required to come to the workplace to work on his side project.)
Under this multiple-part-time-job system, employer health plans will have to become more defined-contribution oriented. That is, instead of the employer sponsoring a health plan allowing the employee to see any doctor for free, the employer will have to contribute actual cash to the worker which can be used to purchase health care. The HSA (health spending account) introduced under President Bush (yuck) allows just this. Also, health plan vendors will have to market directly to employees now, instead of to employers who hire employees. You may wonder how sick or elderly individuals will be able to purchase health insurance when they aren't part of the group workforce of a single employer. The answer is that employees in a region, working for a group of employers located there, will have to be treated as a bona fide "group" by the insurance companies. Health Insurance Purchasing Cooperatives (HIPC's) have been proposed by the government to allow this kind of organizing, but so far, such programs have not been implemented.
I feel that the advantages discussed above (variety, increased breadth of education, financial security, and flexibility) make job diversification a desirable goal for our society.