The key thing to understand about typeface copyright is you can copyright the font file, but not the actual shape of the font (as that video you linked covers).

So say as you said, you had access to a font, you used it in a logo. Then you lost access. It's fine to keep using the logo, any assets you've created while you had access you can keep using. What you can't do is keep using that font file on your machine to start making making new assets. This is why for graphic design fonts are often licensed based on the number of machines they're installed on.

For web, it's often a subscription for a certain number of page views. If you no longer pay the subscription, then you're no longer allowed to serve the font file. Enforcing this however, is really tricky for foundries as you'd expect.

For app use, the license don't account for 'page views' as they figure it's impossible to track (and for the foundry to check). That's often why the figure is more for native apps. They're also kinda taking a guess that companies making apps pay more.

This is why a lot of big businesses will just outright 'buy' a font, so they have access forever with no limitations. If you're committing to a particular font for your brand, it often makes sense to just drop the cash and get it. It's also why so many really big companies just make or commission their own typefaces - it can be cheaper than trying to find some deal with a foundry. A good typeface will take one person about 2-3 years to make, but if you have 1k employees.... no biggie.

It's worth noting most serious foundries don't focus on 'small' customers - they're targeting very large businesses. The pricing doesn't scale down to most normal people, unfortunately - however if they did they'd be dramatically reducing income from the 'whales'. There's also undeniably a bit of price-value bias.

This all varies a bit foundry to foundry, but that's the most common setups and why.

> Say I create a logo with one of these fonts, and immediately cancel afterword. Do I get to continue using the logo? Or is my license to the font technically revoked?

From the perspective of US copyright law, a font file is an odd sort of computer program that generates shapes. The program is copyrighted, but the shapes it outputs are not.

Indeed, US copyright law explicitly states that typefaces - i.e. the shapes printed on paper, not the font program which produces them - are ineligible for copyright. This applies even to fantasy scripts; e.g. the script used in the video game Riven was refused registration on these grounds.

You have to turn it into a path anyways or the program can't show the logo when the subscription is cancelled and the font is no longer available.