I work in the domain, and it is true that many of the startups will almost entirely use free data, like from the sentinel satellites via ESA. It really lowers the barriers to entry, if you have a nice idea.

EDIT:

We actually work close with one startup that sprung out from academia. The founders wrote their masters thesis on object detection and pattern recognition using sentinel imaging. They had basically one product: to detect certain objects. After a couple of years they had gotten a handful of customers (basically they'd receive coordinates to some are of interest, and then tasked with trying to detect something), which afforded them to purchase commercial data (from other types of sensors) for building more robust systems. This in turn grew their customer bas, and they started adding products.

Then they were acquired by one of the largest private space companies.

But, in any case, it all started with access to free data. Would they have started a company like this, if they hadn't had access to the data from ESA? Who knows, but it made it all much easier. And they were able to completely bootstrap the company.