This is a great and valid question along with a helpful citation. Here are some counterpoints:
1) I would argue that that perspective misses a number of travel consumer apps like AirBnB.
2) I've bootstrapped this business and, while I do think that it could eventually morph into a regularly engaging social network or a tool for professional trip leaders (who would invalidate the limited usage point as power users), a healthy lifestyle business outcome would be reasonably ok (if not desirable) by me personally. I don't believe that I could have bootstrapped this company in 2012 (the date of that article) given the startup ecosystem and, frankly, this is a passion project after having previously worked at and founded SaaS fintech companies.
3) I do expect group travel to grow a ton over the next few years if people continue to work remotely. The evidence of mass social alienation is clear and folks have previously unheard of flexibility to travel.