1. Give product away at a loss / or even for free.

2. People say 'great', and start taking advantage of it.

3. Competitors (for profit) can't keep up and slowly stop offering products.

4. Over time the majority of the market is capture by a single company.

5. People become overly dependent on that company, allowing them to build an even bigger, better 'moat', and discouraging any new competitors from emerging.

6. $$$$$$$$$ Prices get jacked up. Customers have no alternatives.

Kind of like an army besieging a walled city. A company doesn't need to build the best product or have the best fighters to win. They just need enough resources to outlast the competition and they automatically get access to the left-overs.