Hey there,
It is a good question but not trivial. Of course we have different types of LSP so lets look at them, individually. I should note that this is theory and variations with products mean that there will be exceptions.
Wax
Without specialist additives, waxes do not really bond to a surface. What bond exists is rather weak. With a wax, IMO, the biggest issue from multiple layers is that you eventually risk almost pulling off the underlying wax when applying over the top. Making it thicker does nothing at all to enhance the bond to the surface but it does mean you have more wax. In theory, the wax is generally degraded from the top down as it 'reacts' with the environment and cleaners. So, in theory, more means that it takes longer to react away what is present.
Sealant
These do (should!) form a moderate bond to the surface. I would suggest that most should not be too picky about what they bond to so they should bond well to themselves. You are not going to be applying as much material as with a wax and, with the stronger bond, you won't really have to worry about de-laminate the underlying layer. Again, with more layers and a top down removal, you should have good benefit with durability.
Super sealants
Almost impossible to discuss here because it depends whether they are non-specific (or not) in their bonding. Some products will not bond too well to themselves but, if they fit with the 'type' they should have a very strong bond to the surface and multiple layers should do nothing assuming you have full coverage (and layers should be so thin as not to alter optical behaviour, as the previous two could).
Much of this assumes removal from the top down. Some people seem to think it happens the other way round but that would suggest something wrong with the surface that meant the LSP was extremely loosely attached and the reality would be that such a thing would still require some force on the top to remove it.
My view, a couple of thin layers of wax are probably fine and should enhance durability and optics. Sealants you can layer away to your hearts content and it should get better with each layer (unless you apply daft amounts!). Super sealants should be single layers, if they need multiple layers, then they either are not so super or coverage was not adequate.
Hope that helps a little.