If you have some command line experience you can rent out some compute and then run it on rented hardware. I am renting an A40 with 48G of vram for $0.40/hr on Vast.ai right now to make cool images. I am still using Big Dream which I think is still based on DALL-E, not DALL-E 2. I couldn't figure out how to run this latest iteration (yet!).

Ballpark answer: ~5 years until this is running on local hardware owned by the average person. Hardware is always improving and the algorithms will get more efficient.

Until then, you'll likely be able to use an API to generate images within the next 6 months.