The last residents at the old Camillus House in downtown Miami moved out before dawn Monday, the power was cut, and a big excavator began gnawing at the walls that for more than 50 years provided shelter, food and solace for untold thousands of homeless people.

The demolition of the shelter’s cramped quarters, which incongruously took place as Miami Heat fans swarmed the neighborhood for the team’s championship parade two blocks away on Biscayne Boulevard, is a signal milestone in city history.

For the long-suffering Park West district, its property owners and city officials, the disappearance of the shelter and its soup line raises hopes that a long-postponed revival can finally get underway. They say the shelter and its often unruly clients, scores of whom occupied the surrounding sidewalks day and night, were a source of blight that kept redevelopment at bay even as the adjacent downtown boomed.

The demolition also means good news for the people Camillus House serves. They are trading a rudimentary warren cobbled out of old storefronts for a new, $80 million campus near Jackson Memorial Hospital designed to get them off the streets for good.

The multi-building campus, which is being built in phases, will more than triple Camillus House’s capacity to 340 people by the time it’s fully done in a couple of years.

It also provides an enhanced suite of comprehensive services, including an expanded residential treatment center for substance abuse and mental-health issues, as well as on-site housing options that range from the traditional emergency shelter to 80 already occupied permanent apartments — and even a kennel for the dogs that some homeless people keep for security and companionship.

“Camillus has been here for a long time in an inadequate facility which has caused a lot of problems,’’ said Daniel Cromer, whose family wholesale-clothing warehouse has shared the block with Camillus House since the shelter’s founding by the Catholic order of the Brothers of the Good Shepherd in 1960. “Their leaving for a bigger and modern facility is going to be a wonderful thing for the neighborhood.’’

If the shelter was considered a drag on Park West, the new campus represents a marked upgrade for what’s also been a hardscrabble neighborhood of auto shops, vacant lots and worn apartments wedged between the eastern edge of the Jackson campus and Interstate 95.

At the 3-acre Norwegian Cruise Line Campus, named after one of its chief donors and designed by the local firm of Wolfberg Alvarez & Partners, Camillus House clients will live amid shady arcades and patios and eat in a gleaming dining room equipped with a state-of-the art kitchen. It’s meant to be secure and self-contained, and a resource for the area, with a community meeting room, a 100-seat auditorium, and space for a cafe and convenience store opening onto Northwest Seventh Avenue.

The echoes of a classical monastery, complete with a bell tower — though without a bell — were deliberate, said Camillus House director Paul Ahr.

“We see all the people who come here as pilgrims. We’re here to provide time to reflect and recover from life on the streets,’’ Ahr said. “What we have now is a place that reflects the dignity of the people we serve.’’

Another big difference over the old: Under a years-in-the-making deal with the city that paved the way for the relocation, Camillus House will no longer feed people off the street, so that the new campus won’t become a magnet for sidewalk sleepers.