Not sure what plants the cars you have been looking at were built at. There can be allot of difference in sealants used (location, style of application, product ...) so don't try and lump them all together.
Challenge that is found today with all the regulations is that most current products don't allow a heavy build up so they textures can be difficult to reproduce and the thickness can be difficult to replicate. Sometimes cooling the product before you apply it can help but it takes some experimenting and finding the best product that works for you.
For the heavy, thick textured applications I've been using a two part product that sets up and though some spray it on I've practiced and found I'm successful in using a brush application as a first step to get the thickness, texture and even runs or curtains where I want them. I then over coat it with a spray to get the edges and fine texture. Texture was not typically uniform across a panel or a seam and you can often see the spray pattern (heavier along one edge and thinner on another for example) in the finished produce so you don't want a machine applied look to the finished product IMHO.
The product is Spectrum Sludge - a product made for acoustical insulation. Others have been successful with products like Lord Fusion and similar spray on products Pick one and practice on a few cardboard models that replicate the surfaces and angles you will be using the product on. Checked today and it looks like a gallon cost a little more than $80. Come down 20% since the last time I purchased some.
Hope this helps
Used for a rear wheel well
Original wheel well sound deadener for comparison
Original that has been rattle canned black over the surface by a past owner