You are right that IP law is fundamentally about time. A more nuanced way to think about it is that IP law provides a reliable framework to amortize the cost of information creation.

Intellectual property is an unusual kind of good in that it:

1. Has extremely high fixed cost.

2. Has near-zero marginal cost.

3. Once the fixed cost is paid, anyone could become a seller for zero fixed cost and near-zero marginal cost.

For example, I've spent the past six years of my life writing a book. That's a pretty high fixed cost. Once I've finished polishing it off, it costs me virtually the same to sell 1,000,000 eBook copies as it does for me to sell one. But, also, it would also cost you nearly nothing to take a copy of that eBook, start selling it, and keep all of the profit. You could even undercut me since you didn't pay the fixed cost anyway so have no expenses to recoup.

Copyright law gives me a window of time where I can use the low marginal cost and protection from #3 to recoup the time investment I made in #1. Without that protection, the day my eBook goes on sale, someone can buy a copy and immediately start reselling their own copies of it as some dirt cheap price.

In a world where that happens all the time, many people would be simply unwilling or unable to invest that high fixed cost and those goods wouldn't exist at all.

There are interesting arguments to be had over how long/large this window of protection and exclusivity should be. But I think no window at all would be disastrous.

> An effective monopoly over customers should be won through superior products in the marketplace

That presumes a world where the marketplace has no influence over which products exist at all. Sure a marketplace that sells my book for $20 and $1 gives customers the choice and they can take the $1. That's clearly superior: same great book, much lower price. But a marketplace where I spend years writing only to have someone else profit from my book is a marketplace where the book doesn't exist as a product at all because I wouldn't write it.

(You might argue that people should be creating information products out of the goodness of their hearts and not for financial gain. That's a nice sentiment, but the consequence of it is that it means that only the rich participate in creative culture since only they have the luxury to create in their free time.)