Here in the Pacific Northwest we keep our boats in the water year around. That means my 1983 model has been floating for about 27 years. I had to recore a portion of the bottom in 2006 from a leak at the top of the bilge that was not completely sealed when built. It was not that bad, but the moisture meter readings concerned me and I could not determine where the water was coming from until we tore into it. The rest of the boat is solid and mostly dry except a couple of deck areas where hardware was not seated properly.
Bottom line is these are solidly built boats that if properly maintained will hold up very well. There will likely be some wet areas, but unless it is excessive, the boat would still be more sturdy than a lot of other boats on the market. Sounds like the surveyor is trying to rip you off a bit. Any boat will need to be checked for wet areas. Use the information from the survey to negotiate a price you can live with and go for it. If the rest of the boat looks and works well that is. If the boat is well maintained you can usually see it in the cabin, motor, running gear and standing gear. If any of those areas are neglected, then the rest of the boat is probably the same.
Just some thoughts from a happy J30 owner. Hope you will be one too.
