In light of Qatar's successful bid for to 2022 FIFA World Cup, perhaps the Hong Kong government should scrap its plan to bid for the 2023 Asian Games and table a bid for the World Cup instead. Since Qatar is in Asia, it is expected FIFA, football's governing body, would not allow bidding from football associations from Asian until 2030 at the earliest. So there is plenty of time to prepare for a bid.
One of the biggest motivations for awarding the 2018 and 2022 World Cups (to Russia and Qatar respectively) is the desire to hold World Cup in regions that have yet to host the event. Since the greater China region is home to one-fifth of the world's population, hosting the World Cup will bring the world's biggest football showcase to an untapped market. This will foster the growth of the beautiful game in the region. With the expected growth in the Chinese economy, companies will do practically anything to be an official sponsor. This would make this World Cup a financially successful one. (The reason why I am considering Hong Kong over China is that the Chinese men's national football team is often jeered by its own fans.)
Hong Kong annually hosts world-class events in rugby sevens and volleyball, showing that Hong Kong has the know-how in organizing single-sport sporting events. Even though local league matches are sparsely attended, the locals are wild about high-level football and friendly matches involving visiting football clubs and foreign national teams are often well-attended. So local attendance will not be a problem.
A World Cup hosted by Hong Kong would be one of the most intimate World Cups ever. With the lack of closed-off football pitches, the fans will have ample opportunity to get in close contact with the world's greatest footballers during training sessions. Most of the stadiums in Hong Kong are small and compact. This helps keep hooligans from stadiums. Other than participating in matches and training sessions, footballers and fans also have the opportunity to enjoy the wide range of leisure activities available in Hong Kong. This enables football fans to get close to the world's best footballers in a more natural setting.
Qatar's successful bid also means that small countries/regions are now considered capable of hosting World Cups. In recent years the top division football league in Hong Kong has adapted the policy of assigning each team to a home stadium. At present 8 stadiums play host to first division matches. Thus as long as FIFA keeps the number of teams participating in the finals at 32 (8 groups of 4), each group can be assigned to one stadium during the group stage and all matches in the group can be held at the stadium. As any pair of stadiums are located less than an hour apart, footballers will not be affected by travel fatigue and therefore able to compete in better fitness conditions. Fans will also be able to attend multiple matches on the same day.
The Qatari national team, at present, is ranked outside the top 100 (using FIFA's own rankings). Thus it appears that FIFA no longer take the rankings and on-field performance of a bidding nation into consideration when evaluating the nation's bid. Thus the fact that Hong Kong is ranked in the 140s is no longer an obstacle in making a bid. Besides, hosting the World Cup will motivate the local football association and clubs to improve youth training so that the host team would be competitive by the time the tournament begins.
Stadiums hosting World Cup matches often become disused after the conclusion of the tournament. Based on current match attendance of local league matches, expansion to the stadiums will be minimal. Thus the stadiums are not likely to become "white elephants", This would make the bid one of the most cost-effective World Cups in history. At the same time, each match will be broadcasted live on each outdoor TV screens, commonly found in Hong Kong, so that fans can still enjoy the matchday experience.
Logically, there is no way Hong Kong will win the right to host the World Cup in the near future (China will get to host the tournament long before Hong Kong gets its turn). However, Qatar's triumph over more technically sound bids shows that FIFA can (and often do) make decisions on a whim. Using some of the justifications given for awarding the World Cup to Qatar, the idea of Hong Kong hosting the World Cup becomes not so far-fetched. (This all being said, I don't think Hong Kong should bid for the World Cup until its on-field performance improves.)