Investing is important for a country to advance and not stand still. It's very similar to a company that needs to invest in itself to not become obsolete. There are different forms of investing that will bring different outcomes. A country can invest in it's infrastructure to make it more competitive international. For example, having good Internet access is a must today. Without it there is almost no chance of running a business, same goes for security. Another form of investing is into knowledge, having better schools and universities makes sure that the population will be more intelligent in the long run. If a country doesn't invest into education than it will be hard to replace the workforce when older employees go in retirement. Also innovation requires investing.