Every source I have come accorss tells me that when you do the acid catalysed dehydration of an alcohol that the mechanism is always the protonation of the oxygen atom to eliminate water, which gives you the carbocation, which nothing attacks, but a water molecule takes a hydrogen from a neighbouring carbon atom to give you the alkene.
My question is, why doesn't, with sulfuric acid, you don't get an alkyl hydrogensulfate caused by the attack of the conjugate base on the carbocation. Then to get your alkene I would assume a water molecule or another hydrogensulfate ion takes the hydrogen from the neighbouring carbon atom and the hydrogensulfate gets eliminated.
Hope the question makes sense!