Well yeah. Time and budget can be limited. The "best" way to learn a language is to travel to a country native to it and immerse yourself, constantly attempting to speak to others. But that may not be accessible in time nor costs to travel and live. The "best way" to learn many topics is to immerse in a community that's a mix of learners or experts. ie. A classroom setting. A place to constantly iterate and quickly correct mistakes. But education is only getting more expensive, and not all communities are equal.

If there's a great beginner textbook out there, that can definitely help. But not every field has its Bart-Sutton easily accessible. But the time it takes doesn't necessarily matter as much as the mastery itself.