Mac OS X was largely ported to Intel by John Kullmann working remotely, close enough. (Several more engineers were added to the project but not until a year and a half after he started.)
I guess it depends on what you mean by “building a new CPU architecture.” Granted, porting an existing one to another existing one isn’t the same thing, but it’s as momentous an accomplishment, no?
Large projects, that require coordination with many people, are difficult to lead remotely. It tends to require building relationship and face-to-face problem solving to get alignment. The most valuable and well-paid engineers in the industry are these.
Projects which are technically difficult, but do not require leadership can often be done remotely. The best fit for a remote worker is someone using technical skills they already have, to further goals that are already defined. Many skilled engineers serve this function.
Maybe people would agree if we change the word “best” to “most responsible” or “most accountable”.