In recent years,. all sellers were less negotiable, because they didn't need to be. Builders will generally estimate their costs and determine the selling price long before construction is complete. That worked in a stable or appreciating market. If you are in a market that has experienced some pricing adjustments, the builder's orginal estimates and selling price might be too high.
If the lake home is an individual custom property by a small builder, you may have more room for negoatiation as compared to a developement. A larger builder is more likely to negotiate upgrades, or offer incentives, vs. cutting the base price. If the builder cuts the base price, it would be difficult to ever raise the base price, unless it is an across the board permanent price adjustment. A smaller builder with an individual property may be more receptive to an offer that represents less than the asking price.
From your description, you might be dealing w/ a single property. Hire a good buyers agent who can give you pricing advice and stragey based upon comps, trends, activity levels, and absorption rates. The asking price may be close to realistic, or more than 30% off, or anywere in between.
If you are dealing w/ a development, I still advise that you hire a good buyers agent who can represent your interests and negotiate on your behalf. If base pricing is not negotiable, you can seek free or discounted upgrades, assistance w/ closing costs, financing incentives via direct payments, or buy downs on the interest rates or points.