Because they might pay you more if they disclose upfront: Two candidates with a similar history may get two different offers because one candidate got paid more

Because they might pay you more if they disclose upfront: Two candidates with a similar history may get two different offers because one candidate got paid more in the past than the other. And then in general, this means that over time, they get paid less too because raises are often percentages. Disclosing upfront not only means that this practice can't really stay as is, but means that you might wind up with some folks that aren't getting paid what new hires are getting paid. If you want to have a 20 year vet, say so in the job qualifications and offer a salary that would attract that group.