Basically, the more sound the network is, the more value it represents.
If the NXT has more value, because the tech behind it is more trustworty, 10 NXT could easily be worth more than, say, 100 NXT.

You could basically own ALL NXT and still have nothing, because no one places value on it, or you could own a few that are worth loads.

So, spending money on hardware is an investment in the value of the NXT.

Edit: the "mining" mentality is a weird mindset.