With the recognition that a brand name or trade name is important for business, there is a trend among large prestigious law firms and even some smaller law firms to rebrand their law firm name to one that is good for branding.
What’s good for branding? A simple one-word tradename, preferably one that stands out. Hence, Milbank, Tweed, Hadley & McCloy is now just “Milbank”.

I believed for years that prohibiting law firms from using a trade name is unconstitutional. There is no rational basis to require law firms to use the name of a partner, especially when the names of partners deceased for many decades are permitted.