Are LEGO cost-cutting with materials?
Since none of us here officially represents The Lego Company, the only possible answer at this moment (if I take your question literally) is "no". We don't know whether TLC has introduced a change in the manufacturing process, if such a modification was made in order to reduce costs, and if such a modification could have resulted in sub-par quality bricks.

The phenomenon you describe can be a result of a deliberate modification in the production process, an honest accidental mistake at one of the manufacturing facilities, or even might be a textbook case of confirmation bias, and it is quite hard to differentiate between these without auditing the relevant factories and your experiences.

The only ones capable of giving an official answer would be the customer support team at Lego, but I guess they would just tell you that they strive to provide their valued customers with the highest quality bricks, and they sorry, but they can't disclose exact manufacturing steps or financial decisions. But they might offer to replace your cracked bricks, or at least might appreciate feedback, so I think you should write them a detailed message about your experience.