The soonest it would happen is the 2030s. I follow the NBA. There are currently 30 teams. Most around the Association believe that the next two franchises will be Seattle and Las Vegas, and afterwards the NBA will restructure from being 2 conferences of 15 teams to 4 conferences of 8 teams.
Vancouver could get in on the next expected expansion of 4 teams that'd stretch the league from 32 to 36. Mexico City might be in the running as well.
Upcoming TV deals are likely to influence Vancouver's odds of getting an NBA franchise. Currently, the largest TV deals are domestic US deals, like TNT, ESPN and NBC, and in these cases, Canadian viewers effectively don't count. More international and online TV deals for the league as a whole would probably increase the odds of more non-US teams in the NBA, like one in Vancouver.
Another factor is that Raptors owners, rogers and bell, are used to having basically no other competition in the Canadian telecomm and sports broadcast markets. I think that they would have the means and motivation to effectively block another NBA team from expanding into Canada.
Vancouver is a larger city than Memphis, don't make up narratives. The team left Vancouver because they were awful, with awful leadership and ownership, and were sold to an American owner as they were not profitable. Before they were even created they failed to reach the NBA's minimum ticket sales requirement for a new team, and Shoppers Drug Mart stepped in and bought 2,500 season tickets to reach that minimum threshold, there was no interest in the team. If the team had been anywhere near good in Vancouver they may have become profitable and still playing there, but expansion rules in the NBA back then were insanely awful. Their first year they weren't allowed a top 5 pick, they weren't allowed to use their full salary cap for 2 seasons, AND they couldn't have the #1 pick in the draft for 3 years, even if they won the lottery. These insane rules, and debacle with their best draft selection in Steve Francis refusing to play for the team led to the team being ASS for their entire time in Vancouver.
I'm pretty sure Memphis is a larger NBA market than Vancouver, where market size is largely a function of (US-centric) TV deals and not local population.
I suppose I didn't clarify that it wasn't the first ownership group that succeeded in moving the team to the US. However, in response to your allegation that I am "making up a narrative", here's how the start of https://en.wikipedia.org/wiki/Vancouver_Grizzlies_relocation_to_Memphis reads:
The Vancouver Grizzlies relocation to Memphis was a successful effort by the ownership group of the Vancouver Grizzlies to move the team from Vancouver, British Columbia, Canada to Memphis, Tennessee, United States.
You said they wanted to move to a larger city, they moved to a smaller city. And what does you posting the first sentence of a Wikipedia article about the relocation mean? That the article about their relocation is about their relocation? The original owners sold to Michael Helsey in 1999 and he immediately started the process of moving the team. Do a little research instead of doubling down, it's okay to learn.
Okay, on account of the big stink you're making, I updated my original phrasing from the more conversational "larger US city" to the more robustly correct "larger NBA market." For the sake of your fellow Lemmy users, I think you could find more civil ways to express disagreement with others online