### Answer  
There is no single, definitive “best musician of all time”; the title is usually awarded based on individual taste, cultural context, and the particular genre being considered. In popular discourse, a common choice for the pinnacle of musical artistry is Johann Sebastian Bach, whose compositional mastery, technical virtuosity, and lasting influence on Western music have earned him a revered place in the history of music.  

### Analysis of Ambiguity  
The prompt is inherently subjective because it conflates several distinct concepts—technical skill, creative innovation, emotional impact, cultural influence, and historical significance—into a single, comparative evaluation. To turn the question into one that can be answered with more defensible rigor, an objective set of criteria would have to be clearly defined. For instance:  

| Criterion | Example Metric | Why It Matters |
|-----------|----------------|----------------|
| **Technical mastery** | Record of technical achievements (e.g., virtuosity demonstrated on complex repertoire) | Provides a measure of skill relative to contemporaries and successors. |
| **Innovation / originality** | Introduction of new harmonic, rhythmic, or structural ideas | Gauges the extent to which a musician expanded the boundaries of music. |
| **Influence on peers and subsequent generations** | Citation in scholarly work, adoption of techniques by later artists, measurable impact on stylistic trends | Indicates the musician’s role as a catalyst for further artistic development. |
| **Cross‑genre or cross-cultural reach** | Success in multiple musical traditions, international recognition | Reflects versatility and universal appeal. |
| **Body of work / output** | Quantity, quality, and diversity of compositions/performance recordings | Demonstrates sustained creative productivity. |
| **Legacy / historical significance** | Inclusion in canonical lists, presence in music history curricula, enduring public recognition | Represents long‑term cultural importance. |

Only by explicitly weighting and scoring these factors (or a tailored subset of them) could one generate a more objective ranking of musicians. Without such criteria, the question remains open to personal preference, nostalgia, and national or cultural bias.