To be clear, you would work with a very small data sample or synthetic data as your objective isn’t to train a model for production use.
Edit: clarity and grammar
For comparison, NVIDIA just upgraded from 40GB to 80GB.
Training usually uses large amounts of data to get your system to recognize a pattern. It generally uses huge memory and compute and generates a model.
Inference will use that generated model to recognize the pattern in new data. It uses significantly fewer resources and can run either very fast or on a smaller system.
I believe the speed of inference may be affected by the resources available during training, where more speed/memory for training can produce better models.
Let's wait and see what Apple Silicon has in store for the iMac Pro and Mac Pro.
You don't have to throw the biggest model you can at any problem you have.