This is not true at all. Salaries for starting lawyers at "BigLaw" firms are generally fixed...but only by firm and by location. So Firm A in NYC pays $XXXk but their LA office only pays $YYYk. Firm B probably pays close to $XXXk in NYC but might pay $ZZZk. And if you go down to the smaller firms, they could pay anywhere from $40k to $XXXk based on location, type of law, etc.
After the first year, very few firms are lockstep with regards to raises...in the past few years, I think only 1 or 2 major firms is still on the lockstep model. Raises after 2nd year are almost universally based on performance, which depends heavily on technical skill (technical meaning legal, not programming, skills).
It seems -to-edit many more than one or two of this hundred https://www.vault.com/best-companies-to-work-for/law/top-100... are still paying lockstep.
Cravath still lists lockstep raises for years 1-7. Skadden years 1-8. Latham 1-9. Davis Polk 1-6. Etc. Are the firms reporting one thing but actually doing something else?
They rest don't do lockstep anymore. On paper they start with lockstep, but actual raises are based on performance, location, legal group, etc. I have enough friends at Skadden and Latham in different offices to confirm that.