"Hong Kong has been important because China had a capital shortage. It was looking for foreign capital. Now, China has a capital surplus," he said. "I don't really [think] an offshore financial center will be so significant in the future," as once China's currency (Exchange:CNY=) becomes fully convertible, global deals will likely be handled in Shanghai, he added.
"Economically, Hong Kong ... has been marginalized. I don't see how this process can be reversed," Xie said.
The relative size of Hong Kong's economy to China's has certainly faded.
"Hong Kong's purpose as a trade route into China has shrunk over the past 20 years, whereas it has become more dependent on China for its trade," noted Mark Matthews, head of research for Asia at Julius Baer (Swiss Exchange: BAER-CH), in a note Tuesday. "In 1997, Hong Kong's economy was 18 percent the size of China's. Today, the figure is down to 3 percent. The mainland produces 30 times as many goods and services as Hong Kong," he said in a separate note Monday.
Indeed, Fitch estimates that Hong Kong's gross mainland exposure was equivalent to 314 percent of gross domestic product (GDP) as of June of this year, up from 70 percent in 2008, with 38 percent of its banking sector assets based in China.
Other analysts have expressed concern that the protests come just as Hong Kong already faces increased competition for investment from mainland China. A new trading link between the Hong Kong and Shanghai stock exchanges is due to launch in October, allowing investors outside China to access mainland-listed A-shares.
"In the medium term on the financial services sector, which represents around 16 percent of GDP in Hong Kong, whether the further disruption forces financial services companies to consider alternatives in the region [will be watched,]" Toby Lawson, head of financial futures and options at Societe Generale (Euronext Paris: GLE-FR), told CNBC. Some analysts have already noted that much of the region's wealth-management business has already shifted toward Singapore.
Lawson also noted that tourism accounts for around 5 percent of Hong Kong's economy and the protests may take a bite out of the flow of travelers from China, who now have greatly increased travel options.
To be sure, not everyone expects Hong Kong will lose its status as a financial hub.
"Obviously, when you have this sort of [protest], it will make investors think, is there a better place," Ronald Arculli, senior partner at King & Wood Mallesons and the former convenor of Hong Kong's executive council, told CNBC.
But he doesn't expect a major shift anytime soon.
Read More Why Hong Kong unrest scares markets
"The market in Hong Kong is international. The market in Hong Kong is not entirely made up of home grown companies. We have the major mainland companies listed here. We also have some very important overseas companies listed here. We have a very vibrant currency market [and] a very important renmimbi settlement trading center," he said. "All those things you don't get overnight. And equally, hopefully, you don't lose overnight."
-By CNBC.Com's Leslie Shaffer; Follow her on Twitter @LeslieShaffer1
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