Generating data this way is extremely difficult. The true population characteristics of prices are unobservable, we can only with with samples of the population

Generating data this way is extremely difficult. The true population characteristics of prices are unobservable, we can only with with samples of the population. This means that any attempt at generating data is highly likely to add errors that are difficult to quantify. This is a fundamental difference to disciplines where ML is most successful: in finance you can’t meaningfully generate new data, you can only work with what has been historically recorded, and that is often not relevant to how the market will behave in the future. You can always generate more cat images for a ConvNet to learn, you can feed it photos from multiple angles or even 3D imagery. None of this is available for market data unfortunately.