It is the ideal for any business, but it definitely is not for the consumer or the economy, and this is why governments enact anti-trust legislation. The government is supposed to enforce against monopolies, but unfortunately in the US government this has been undermined. Matt Stoller has a great book and e-newsletter about monopolies past and present vs. government.

I think most tech startups would aspire not to increase prices, but increase market share such that selling a high volume at the original price is enough to cover the investment and start to turn a profit.

Of course you might price your product less, but from a certain point of view it's less predatory than it is just fair market price. When you are a startup with no customers, your first customer is taking a chance on you. They have no idea what the quality of your product is. They have no idea if you're going to be around to support it in 6 months. All that uncertainty should be factored into the price. If you are a more established startup then the fair market price for the exact same product all other things held equal, should be higher.

It's not a new concept, either. It was something I learned about in introductory business courses: https://en.wikipedia.org/wiki/Loss_leader

There's a school of thought that because digital goods have no cost per additional unit created, that they will always tend towards being free in a free market. Hence, the only way to get people to pay for a digital good is to have a monopoly.

I think the difference might be in that startups often do not have their own dominant & profitable products that they can leverage to undercut the profit in complements.

Yes this this is a very common strategy, not only in tech but many businesses