Rutherford chased off most of Pastor Russell's flock by his personality, tactics and ESPECIALLY because of his very public failure in predicting 1925.
Bible Student groups by various names (using Russell's theology) had sprouted like mushrooms.
Like Constantine, Judge Rutherford faced a divided kingdom. He needed a device to weld the "faithful" into solidarity before securing total power.
Three things are worth noting.
1. Judge Rutherford's mind was trained as an attorney and jurist. His world had been Circuit and District Courts solely interpreting the letter and
intention of the law. A court of law requires WITNESSES and evidence. Consequently, he thought of BRANDING his group legally: JEHOVAH'S WITNESSES.
2. In Biblical Greek the term "witness" means "martyr". Rutheford intended to demonstrate through the martyrdom of his followers--how publicly righteous and chosen they were because these "Witnesses" (Martyrs) were more persecuted than the others.
3. By re-interpreting the meaning of Romans 13:1,2 he turned the members into law-breakers, civil protestors and Supreme Court test cases to make a high profile name for his new religious BRAND.
(The District and Circut assemblies carry over the legal flavor of his naming process).
The theology/Doctrines of Russell had been about the invisible PRESENCE since 1874 of Jesus Christ as King.
Rutherford got rid of that idea and substituted "Announcing Jehovah's Kingdom" and the Society's books began teaching
the purpose of JW's was VINDICATING (a legal process) by Witnessing in clearing JEHOVAH'S NAME which Satan had challenged in the Universal Court of Law.
By making a fetish out of the name "JEHOVAH" and branding his invention as Jehovah's Witnesses, Rutherford accomplished his mission.
Bible Students were very low profile and boring. Judge Rutherford's JW's were in court winning flag salute cases, preaching ordinance cases, blood transfusion cases, etc. and getting the members thrown in jail, beaten up, tarred and feathered, imprisoned and sometimes killed.
He made MARTYRS of the members (i.e. he made WITNESSES) out of them.
As far as the term Yah-weh (the scholarship on this is more latter day than Rutherford's era.)
Had the ACTUAL name's pronunciation been the genuine concern of JW's they would have up-dated (new light) the spelling.
It never has been.