Good question, my thoughts: 1) to apply an LP or MILP to a practical problem that a business cares about requires a rare mix: one or a small number of people to have domain knowledge, knowledge about LPs/MILPs, and a good fit to the problem at hand. 2) the types of problem where LPs/MILPs reduce business expense is (currently) different from the spaces where ML has found success. This could change, but LPs have been applied extensively to strategic/logistics/planning applications, which aren't as approachable as applications of chatGPT, xgboost, etc. 3) LPs - since they are convex and provide global solutions - don't naturally support a kaggle-type competition that pits individuals and teams against each other. 4) there exist good open source solvers and very nice APIs (scipy, cvxpy, cvxopt, etc for example) but also high-cost and high-performance commercial solvers that businesses do pay for (Gurobi, CPLEX, etc).