Sitting in the Downtown Cocktail Room a week ago, Tony Hsieh was sharing shots of Fernet, the pine-tree-in-a-bottle spirit, with a small crew of technophiles. Among the group were two guys from Pixar who are about to unleash a gizmo or software that works like the electronic comic book in the movie Big. It lets users direct the characters in a movie, game or TV show, so the story unfolds as the viewer wants it to.

Or something like that.

Anyhow, it’s not pie in the sky anymore. It’s doable. It’s being done.

Maybe the idea of doing something once thought impossible piqued Hsieh’s memory because he suddenly turned to me and asked, “So do you believe it now?”

I knew immediately what he meant. Shortly after his late-2010 announcement that Zappos would move its headquarters into the abandoned City Hall in late 2013, he talked of redeveloping Downtown, as well. He described his vision for the area as something similar to the hipster-y Austin, Texas.

Today, the vision has changed. No one talks about Austin anymore; now it’s Las Vegas, with the idea being to create a progressive, technologically fertile area that is distinctly our own. Maybe I rolled my eyes when Hsieh first espoused his grand vision. I had major doubts, some born of a textbook journalistic need to question everything and some from my experience with the myriad scammers who have flocked to Las Vegas over the years, trying to pawn off ideas for multimillion-dollar high-rises or bizarro casinos without the financial backing to pull them off.

How about a hotel shaped like Michael Jackson’s white glove? Or one that looks like a flying saucer? Bob Stupak wanted to build a timeshare that replicated the Titanic, tilted like it was sinking. No one bought into that idea, but somehow the shimmering gold Trump Tower got built.

That said, I’ve always been a skeptical sort, even before moving here. But after Hsieh’s 2010 announcement, I did something that went against my grain. I held back on scrutinizing his plans. I wanted to give it a chance. I could have easily found critics to say “impossible” or “stupid” or “don’t waste your time,” but why tear down an idea before it has a chance to germinate?

Two years have passed since then. In just nine months, more than 1,400 Zappos employees will start working in the remodeled City Hall/Zappos building at Stewart and Las Vegas Boulevard. And already, Downtown feels different. Police officers I know say it’s completely safe to walk from Las Vegas Boulevard east on Fremont Street to 7th, even 8th Street. At night. They talk with the pride of an owner about how they want to stretch that zone of safety over to 11th.

For the first time in decades, all the storefronts in a one-block stretch of Fremont from Las Vegas Boulevard to 6th are filled with businesses or are being remodeled. It’s a fun, energizing place to be. The closest thing I’ve felt to the electric excitement on East Fremont is the buzz you feel walking in Manhattan. It’s a small area, but it’s here.

And yet, skepticism is setting in. I almost want this development to stop in its tracks. It’s a cozy setup, this East Fremont resurrection. It’s small and manageable. Scrappy, even. You see Don Welch, the small-business developer for the Downtown Project, chain-smoking cigarettes outside as he handles a million phone calls from people around the world wanting to get here and fast; everyone meets at the Beat coffeehouse to talk business; the bartenders in most of the bars know customers by name.

It feels like that’s going to change very quickly.

Hsieh has talked openly about all the plans he’s been working on for a year or more and how many of those will be unleashed in the next few months. People will see new businesses everywhere. Suddenly.

The shipping container park, a Jetsons-looking thing at 7th, will be done by this time next year. So will the geodesic dome/Holodeck-thing that is the park’s centerpiece. Two restaurants are going to go into the ancient John E. Carson motel at 6th and Carson. And Hsieh and investors have reportedly spent almost $50 million buying other properties all the way down to 14th Street. That includes old motels such as the Ferguson and the Downtowner. What will go in there?

I worry that the quaintness of Downtown will disappear with growth. In a way, that’s an LOL-able worry, given the fact that four years ago no one would have thought of using the word “quaint” in connection with this once drug-addled section of the city. But people have short memories. The dregs of Fremont Street are becoming distant images.

Zappos’ motto, “delivering happiness,” was partly born of a long process of business trial and error. Hsieh made money; he created a corporate empire; but he also witnessed the disappearance of the camaraderie and fun that was part of a new business’ early years.

He fixed that with Zappos. As the company grew—it has reached annual sales of $2 billion—he figured out how to maintain the same loose, scrappy feel it had when he started it.

So the skeptic’s question has changed. Downtown is happening in many ways Hsieh envisioned. The new question is: Will it always be this cool? Can one man’s vision not only change an entire area but also alter the mindsets of people who move there to live and do business? We’ll know soon enough.

For now, savor what’s there. It’s going to change—quickly.