It is unrealistic for people to work at the same company for their entire lives.
The world is changing rapidly than ever before because of technologies. Nowadays, there are more job opportunities available than it was in the past. Thus people are tend to change their job depend on their income. However, I believe that people should stay one company is more beneficial than they just change company rely on income for two main reasons: People who works at one company for long time have more chances to promote and also they can even improve their abilities as well.
First of all, people who works at same company for thier whole lives they would have more chances to promote. This is because they understand their company and system, this allow them to appeal their their abilities quite well. This means their income would increase since they get promoted. Therefore, people who stay at one company will earn more money in long term than people who just change their companies depend on income. For example, My cousin got much job opportunity from other companies and those companies suggested him higher salary than the company he was in. However, he had not decided to change because he already got used to his company and also he understanded how his company operate. After all, recently, he have promoted to higher position in his company and he gets more pays than the other companies suggest him.
Seconld, A person who works for same company for long time, they would likely have more chances to improve their abilities because of his/her company's support. This can happen because the company not only know the person well but also they trust the person's abilities. Therefore, the company offer him more chances to progress huge projects. This allow him to develop his career and experience valuable lesson. Since a person works for same company would have much more opportunities because of trustship between company and person.
In summary, some people believe that moving companies around is good idea for them. However, I firmly argues that working for same company for their whole lives is better because of income and opportunity. Also I would like to say that people should be proud of their companies.