That would imply, that (globally) we spent significantly [EDIT: remove -less-, insert:] more on advertising before the advent of personalized targeting.
Got confused while writing by the observation that ad expenditure is rising year after year. So clearly, the "savings" allegedly attributed to personalized targeting have not translated to advertisers.
Not necessarily, cost reductions can increase, decrease or have no effect the total expenditure on goods. The total effect is quite ambiguous depending on the income and substitution effects.
