As far as evidence against theory, evidence achieved through carefully controlled experiments is always preferred. In reality, I don't know of an easy way to do this. Would you run two "identical" cartridges for a predetermined number of hours with one being installed in a linear tracking arm and the other in a pivoted arm and after said hours are up, would you then examine/meaure each cartridge for changes to the suspension and cantilever alignment? I can see lots of variables creeping in here that could affect the outcome. The reality is I don't know how practical this experiment would be.
As far as cartridge manufacturers giving us any meaningful info on this debate, I am old enough to be cynical enough to think that we couldn't depend on it. Aside from the issues that manufacturers may have no idea what type of tonearm was tracking their cartridge before it was sent back for a rebuild, politics and money are pervasive in everything. Even if it was true, I don't know that cartridge manufacturers would tell you that using a linear tracking arm will shorten the life of your cartridge. Not only do they have to worry about lost sales to potential linear tracking arm customers, they would also most likely incur the wrath of linear tracking tonearm manufacturers.