My first guess would be it has lots of uncompressed images or badly compressed videos as artifacts.

Same, but games run uncompressed assets as an optimization measure to trade disk usage for CPU usage, depending on which is the bottleneck for their particular game (iiuc)

So it'd be surprising to me if a developer chose to use uncompressed/lightly compressed assets, and compressing them caused performance to increase; because you're intentionally choosing the tradeoff in the opposite direction the developer did

Of course, there are game developers that are less technical and may not have knowingly made that tradeoff in which case all bets are off, but the games made by those developers tend not to be the kind that require beefy machines to run at 60fps+

The right tradeoff for compression ratio can change with just a few years of technological progress, or even quicker if it's a half-assed port from console to a high-end PC. There are similar issues for a game's decision of how many threads to spawn based on the CPU's core count. The developer's assumptions may not have been right to begin with, and even if they were, they're not likely to stay right for long.

Exactly. Guaranteed SSDs and a spare CPU core have made compression almost always faster.

Being able to rely on fast storage makes compression less necessary for performance reasons. But the higher price/GB of SSDs mean users have a stronger preference for games to keep the install size under control.

There was a time when console games would avoid disc seeks at all costs, even duplicating uncompressed assets. Compression can easily interfere with laying data out in blocks to read sequentially.

That’s not a problem with SSDs and most machines have more cores or even dedicated hardware decoders. Of course it’s also more worthwhile to compress since SSD storage is comparatively more expensive.

It never ceases to surprise me that people still embed 5+ MB resolution photos on their sites, then use them scaled down to thumbnail size, but here we are.

Put a chunk of work into optimising the images on a site once, of course as soon as I left this was undone.

The office we worked in had really fast internet, but I was fixing things for the users.

My power company’s outage website is about the only site I can’t access through my cell phone when our power is out because even the “low bandwidth” version is a bloated farce.