He did say that and he's wrong. x86 isn't particularly dense and RISC-V compressed is denser. However the insane encoding is burning real power, takes up real area, and is a real limiter for decoding. Dear Linus has an irrational love for x86.
He wrote those comments in 2003. The instruction decode logic takes up less space with each new chip and process shrink. These days I don't think it really matters much.
