What Drives Growth? Investment or Consumption?

Hypothetically, suppose an individual, we'll call her Jane is unemployed and takes a chance on the lottery.  She wins $500 and has to decide what to do with it.  She decides, she is going to be generous and use it in a way that is best for the economy.  Here question is, should she go out and consume, splurge on a new laptop to play on facebook, twitter and whatever other leisure uses that a computer can be used for?  Or should she invest the money?

So she thinks about the economic consequences of each.

If she buys a $500 computer, she can have a lot of fun, and her spending will provide revenue to HP computers.  That is certainly good for the economy, right?  Because their profit goes up.

Then she considers possible investments, and gets an idea.  She would "invest" in a computer, and use it to do some contract work designing software for small businesses.  The very same one she would have bought to spend her leisure time on.  HP still gets the same $500, so they, their investors, and everyone down stream from that purchase gets the very same benefits.  So the economy gets the same benefits either way, and she benefits, because she can generate herself some income that she can spend to help the economy even more.  She also realizes that this is much better for herself as well.

As she develops her skills, her customer base grows, and their orders and demands grow.  She soon realizes that she cannot handle it all herself.  She asks her sister, who she trains, to join her.  She buys another computer, and the two of them continue to attract new customers and make enough money to cover their expenses with a little left over.  Soon, that leftover capital gives her an idea.

If she hires 2 more programmers and a marketing professional, they could expand further.  So she makes those hires and buys 3 more computers and a printer for the marketing materials.

the businesses is really running great, she is making a good living, and she feels bad.  She sought to benefit the economy and those around her, but has, instead, made herself modestly wealthy off of her $500 win.

This doesn't last long, as she soon realizes, she has done both.  While maximizing her business returns, and thus her own earnings, she has bought 5 computers and a printer, and now, including herself, employs 5 people.  She has grown the economy by 5 jobs, 5 computers' and a printer's worth of earnings for HP and created products that allowed other businesses to grow.

That is a lot of economic benefit, she realizes, and is extremely excited and quickly gets back to putting all her effort in to growing her business.

So investing the $500, led to the various benefits throughout the economy and for herself.  Buying a computer for fun would have done far less.

Clearly, investment is the bigger driver of growth.  One would think that economic policy would be set in ways to maximize investment and production.  Right now, it is the opposite.  Work and investment are punished.