Although it's not a purely software industry, embedded development has a lot of opportunity for bare metal hand tuned optimizations
Cryptocurrency requires money to pay for transactions. The most performant pieces of smart contracts by the best firms are written in assembly, as this saves money. The crypto industry has been the primary financial motivator for advancement in formal verification technology over the past few years.
Embedded development but specifically low-powered embedded development. Not everything is wifi and cell network, sometimes you have devices that wake up, broadcast a signal over LoRa or Zigbee and return to sleep. Specialized batteries can last 10+ years. You see some of this stuff in smart lighting remotes and sensors.
However much of this was done in the interest of as few cpu cycles as possible rather than raw speed.