Amazon CEO Jeff Bezos Alex Wong | Getty Images

Just days before Amazon announced the big winners of its HQ2 sweepstakes, CEO Jeff Bezos had to address a separate but related concern among employees: Where is all this headed? At an all-hands meeting last Thursday in Seattle, an employee asked Bezos about Amazon's future. Specifically, the questioner wanted to know what lessons Bezos has learned from the recent bankruptcies of Sears and other big retailers. "Amazon is not too big to fail," Bezos said, in a recording of the meeting that CNBC has heard. "In fact, I predict one day Amazon will fail. Amazon will go bankrupt. If you look at large companies, their lifespans tend to be 30-plus years, not a hundred-plus years."

The key to prolonging that demise, Bezos continued, is for the company to "obsess over customers" and to avoid looking inward, worrying about itself. "If we start to focus on ourselves, instead of focusing on our customers, that will be the beginning of the end," he said. "We have to try and delay that day for as long as possible." Bezos' comments come at a time of unprecedented success at Amazon, with its core retail business continuing to grow while the company is winning the massive cloud-computing market and gaining rapid adoption of its Alexa voice assistant in the home. But some employees are expressing concern about the pace of expansion. Amazon's workforce has grown by more than 20-fold in the last eight years to over 600,000 employees, and the stock price has more than quadrupled since 2013. The company has caught the ire of President Trump, who has employed personal attacks against Bezos, and is now catching flack for demanding that cities spend a year coming up with a roster of incentives attractive enough to woo Amazon's HQ2. This week, the company announced it will open offices in New York's Long Island City and the Virginia suburbs of Washington, D.C., with plans to add 25,000 jobs in each location.

This isn't the first time that Bezos has addresssed the issue of his company's scale with employees. In an earlier all-hands meeting in March, Bezos was asked whether tech companies like Amazon need to be more closely regulated because of their sizable market power and influence. "It's a fact that we're a large company," Bezos said, according to a recording. "It's reasonable for large institutions of any kind, whether it be companies or governments, to be scrutinized." Several Amazon employees, who agreed to speak with CNBC on condition that they not be named because they're not authorized to talk about the issue, said that government regulation and the potential for antitrust violations are big concerns among staffers as they look at the company's future. Amazon is expected to capture 48 percent of all online sales in the U.S. this year, up from 43 percent in 2017, according to eMarketer. Its AWS service is by far the leader in cloud computing infrastructure, capturing about 34 percent of the U.S. market, Synergy Research Group said in a recent report. An Amazon spokesperson didn't comment on the all-hands meeting. Regarding potential antitrust issues, the representative pointed to a Wall Street Journal interview with Jeff Wilke, Amazon's CEO of the worldwide consumer division, in which Wilke said the company is engaged in a diverse group of businesses and accounts for "less than 1 percent" of the global retail market.