The Civic and the Accord have grown quite a bit since their creation.

First gen Accord, from Wikipedia: Length 4,450 mm (175.2 in) (sedan) - Width 1,620 mm (63.8 in) (sedan) - Height 1,360 mm (53.5 in) (sedan) - Curb weight 898–945 kg (1,980–2,083 lb)

Current Accord: Length 4,970 mm (195.7 in) - Width 1,860 mm (73.2 in) - Height 1,450 mm (57.1 in)

It's now 520 mm (20.5") longer, 240 mm (9.4") wider, and even 90 mm (3.6") taller.

The Civic has gone through a similar transition over its lifetime.

Unfortunately, it's hard to compare other brands because so few have had such long-running nameplates, so you have to start comparing different models in the same market, which I'm too lazy to do.

It's worth noting the curb weight has gone up dramatically, too. The current Accord is 1,469 - 1,488 kg (3,239 to 3,280 lbs) based on a quick Google search (it's not in Wikipedia). So it weighs more than 1.5 original Accords.

Even cars aren't immune to size inflation.