From what I understand of both the recent tweets and both of their fairly radical/extreme (and mostly correct) views about abstraction being a net negative, the criticism is less "Mighty doesn't work" and more "We shouldn't need to use an app like Mighty to get good performance on a basic website".
Sure, but the disconnect seems to be that Mighty is advertised for people who essentially use their browser as an OS (I see Figma mentioned a lot), rather than people who just want to do basic browsing.
I think Mighty has unfairly taken the brunt of a lot of growing discontent with bloat on the web. I'm not ready to fork over $30+ for faster browsing, but I'm glad someone is working in this space, because I genuinely would like to rent a fast virtual computer for the occasional video editing task and think Mighty is a step in that direction.
At minimum it seems like I’d have to choose an instance size, an OS that was compatible with my software, install the editing software, mount a common storage location with my footage, etc.
What I’d like to see is a service that let me add my credit card, click a button, and launch a video editor on a high-RAM machine that I pay for the hour (including the software license fee).