Which financial avenue in astronomy represents the most substantial financial undertaking for someone aiming for a career in the discipline?

The figures associated with four years of education

When comparing the three primary financial avenues—formal education, serious hobby pursuit, and professional affiliation—the commitment required for formal education is clearly the most significant financial undertaking for an aspiring career astronomer. The costs associated with obtaining an undergraduate degree, which include multiple years of tuition, fees, housing, and supplies, accumulate to tens of thousands of dollars annually, totaling hundreds of thousands over four years for many pathways. This dwarfs the recurring annual dues of professional societies or even the large initial outlay sometimes required for advanced hobby imaging equipment.