There have been plenty of times where the opposite is true: Storing highly compressed data and decompressing it in RAM is much faster than loading uncompressed assets.
Which is the primary problem: Computers are so varied and so ever changing that if you are optimizing without hard data from your target hardware, you aren't optimizing, you are just doing random shit.
Add to that, game devs sometimes are just dumb. Titanfall 1 came with tens of gigabytes of uncompressed audio, for "performance", which is horse shit. Also turns out they might have been lying entirely. Titanfall 1 was made on the source engine, which does not support the OGG audio format their audio files were in. So they decompressed them at install time. They could have just used a different audio file format.
Which is the primary problem: Computers are so varied and so ever changing that if you are optimizing without hard data from your target hardware, you aren't optimizing, you are just doing random shit.
Add to that, game devs sometimes are just dumb. Titanfall 1 came with tens of gigabytes of uncompressed audio, for "performance", which is horse shit. Also turns out they might have been lying entirely. Titanfall 1 was made on the source engine, which does not support the OGG audio format their audio files were in. So they decompressed them at install time. They could have just used a different audio file format.