Back in the early days that was a problem as well, but things were better for quite some time even with dmcrypt in play.
Then someone at Google landed a change prioritizing dmcrypt throughput for their use case, and many on desktop linux using dmcrypt suffered for years because of it.
Ah, the "Linux is for servers" problem. Linus thinks the desktop is important, but most contributors work for companies that do server stuff or have mostly server paying customers...
Linux has better RT performance than windows or macOS (or almost anything else that isn't actually an RT OS). That took a lot of work and it didn't come from the server crowd.
Then someone at Google landed a change prioritizing dmcrypt throughput for their use case, and many on desktop linux using dmcrypt suffered for years because of it.