There is power and there is power. Back in the 70s and 80s, it was almost impossible to purchase a modest car with significantly over 100 HP, and small cars had 60-85 HP. It was adequate, but certainly not surplus power. Top speeds typically fell short of 100 mph, but that was ok, since the speed limit was 55mph. Even the Corvette in 1975 had only 165 HP.
Fast forward to today, and most small cars have 130-200 hp, with only the smallest cars having under 120. The Chevy Cruze has 138 HP. The Mazda 3 has 167 (more than a '75 'Vette). My experience is that virtually anything built today will outrun virtually anything from 35 years ago. Today's cars will cruise the interstate effortlessly at 75-85 mph, while 35 years ago, most cars were pretty close to topped out at that speed.
I drive "older" cars (a '95 and an '01). The '01 will run circles around the '95, up to about 70mph, when the roles reverse. When I have a chance to drive newer cars, I am always struck by how much more acceleration they have than my cars do.
I suspect that that may not be linear when towing, particularly with an automatic transmission, however. New cars are geared for optimum cruising efficiency, while my '01 takes more of a "shoot up the middle" approach, keeping the engine revs higher, which keeps me more in my peak power curve. If you work the gears on your new car manually, and run the revs up into the power curve, a new car would have more power, at the expense of the gas mileage.