I have noticed that with laser hair removal, the hair that regrows is alot finer but it regrows to the same length as it was before and sometimes longer. I was wondering if this was the case with electrolysis or do the hairs get shorter as well?

Hairs treated with electrolysis typically don’t regrow at all. The hairs in close proximnity tend to grow thinner. Any hair that was treated either in the wrong phase, or was mistreated in any way, could grow back thinner and weaker as well, but with a good practitioner, 60 - 80% of the hairs treated would not come back. You just must remember that you don’t know what hairs got good treatment unles you take a before picture, an after picture, and another picture one year later on the same day to see the difference between the 3 pictures. Hair you see in the weeks following your treatment have nothing to do with the hairs treated in your appointment.

Over time would the weakened, finer hair eventually become thick again as the body repairs the damage done to the follicles?

The body would not rebuild the thickness of the hairs under normal conditions, as the thickening of hairs is a function of increased blood flow, and or hormonal imbalance.