I agree wholeheartedly with this. In fact, if Mathematica were open source, I feel it may even encroach upon machine learning applications.
Since finishing up in university, I have sorely missed my free access to a fast and ergonomic symbolic equation solver. Sympy is an unsatisfactory substitute.
For my cases, when during R&D (data science for weather/geo/agro) I rarely need to work with formulas in symbolic representation, Sympy works enough. Cases like combining 2 equations into 1, simplifying, defining numeric coefficients, and printing formulas in TeX representation.
Since finishing up in university, I have sorely missed my free access to a fast and ergonomic symbolic equation solver. Sympy is an unsatisfactory substitute.