I don’t think Karachi & Gwadar are really in direct competition in the way many people assume. Karachi Port has been Pakistan’s primary commercial maritime hub since the late 19th/early 20th century & mainly serves Pakistan’s own import-export economy, industrial base & massive urban population centered around Karachi itself.
Gwadar’s intended long-term role is somewhat different. Its strategic value is tied more toward regional transit connectivity — particularly western China through CPEC, Afghanistan & potentially the Central Asian republics — rather than replacing Karachi as Pakistan’s main domestic trade port. So, comparing a century-old mega port-city with an emerging strategic transit hub still in its early development phase is not entirely justified.
That said, I do agree Gwadar’s population & economic footprint will likely expand substantially over time. Much of the regional connectivity infrastructure has already been established through CPEC links, the Makran Coastal Highway & the new international airport. Gwadar Port is also undergoing major rail integration under CPEC, including the proposed 1,087 km Jacobabad–Gwadar rail line & the 680 km Gwadar–Nok Kundi connection aimed at linking the port with Pakistan’s wider rail network & regional trade corridors toward western China & beyond.
So, the real question now is not whether connectivity exists, but how quickly industrial activity, transit trade, logistics & supporting economic ecosystems develop around that connectivity over the coming decades.
There's no reason that Karachi couldn't also serve as a regional transit hub.
A port is a port, after all. And existing traffic flows are the starting point for a hub