Yes, you can clone a clone, and you can do it indefinitely in theory. Every cutting is a genetic copy of the original mother, so the DNA does not degrade with each generation. A clone of a clone of a clone is still the same plant.
In practice, most growers keep a dedicated mother in veg for cutting rather than cloning from clones. The reason is vigor. Each cutting is stressed when it's taken, and repeatedly cloning from already-stressed plants can compound minor issues over time — slower rooting, smaller structure, weaker early growth. Keeping one healthy, well-fed mother in a corner of your tent gives you consistent, high-quality cuts every time.
The bigger risk is disease. If the original mother has HLVD or any other latent pathogen, every clone from every generation will carry it. No amount of clean tools or fresh rockwool at generation 7 will undo what was already in the plant at generation 1.
This is why sourcing and testing matter more than how many generations deep you are. A 10th-generation cut from a tested, vigorous mother will outperform a 1st-gen cut from an unknown source every time.