It is, in quantities that are compatible with a modern lifestyle. Sure, if you're gonna run marathons every weekend, you will lose a lot of weight from that. But that's not possible to achieve while leading a normal modern life (full time employment, a relationship, children).

I think it is doable in a modern lifestyle, but that most people don't make it a priority.

Most people waste a shocking number of hours out of every day scrolling, watching TV etc, and just take it for granted as part of a "modern lifestyle", but it's just an optional way to spend time, and not very productive.

I have full time employment, a relationship, children, and manage to get our for 1hr of running almost every day. (And find time to debate with strangers on HN XD)

1h of exercise a day is great for your health, but that's still only going to be a minor contributor to fat loss. Adjusting your diet is going to have a much, much higher impact on weight loss than 1h of (moderate) exercise/day.