The law of dimishing marginal returns in action, to some extent.

With that being said, I imagine that it depends on the goals of the individual. Burning calories, for instance, is a worthy pursuit and walking helps a bit.

For those also wondering about rough calorie equivalents of 7000 steps in other forms of exercise:

7000 steps ≈ 280 calories ≈ 3.5 METs

- Yoga (flow/vinyasa) – 3 METs – 82 minutes

- House cleaning (vacuuming, mopping) – 3.3 METs – 74 minutes

- Brisk walking (4 mph / 6.4 km/h) – 3.5 METs – 70 minutes

- Elliptical trainer (moderate) – 5 METs – 49 minutes

- Swimming (moderate) – 6 METs – 41 minutes

- Basketball (half-court, casual) – 6 METs – 41 minutes

- Bicycling (moderate, 12–14 mph) – 7 METs – 35 minutes

- Rowing machine (moderate) – 7 METs – 35 minutes

- Soccer (casual) – 7 METs – 35 minutes

- Light jogging (5 mph / 8 km/h) – 8 METs – 30 minutes

- Strength training (circuit, vigorous) – 8 METs – 31 minutes

- Running (6 mph / 9.6 km/h) – 10 METs – 25 minutes

- Jump rope (moderate) – 11.8 METs – 21 minutes

The exact number seems to vary sure but it seems at least broadly correct so calling it a myth seems a bit strong