It's great plan and historically speaking, most of these plans only stay on paper in someone's desk, nothing actual happened. Chinese are not giving free meal. We will have to wait and see.
Economically, we are in a big hole and to dig ourselves out of it, will require some sacrifices. Is establishment willing to make that sacrifice?
That is for them to decide; if they can bring Saudi, Qatar and China together to build such a secure corridor. Considering Saudi wants to contain Iran, it would be a way to do so. A cheaper way (upfront) but politically more costly way would be via Afghanistan. Less cost to the Saudi-US and Saudi-India relationship, while still creating the economic entanglement to protect the nation from a blockade.
Either way, the establishment should be leveraging this moment to shift the paradigm on all stuck issues for the nation. This year is really a unique moment, and doubtful the likes of will be align again.
Btw, this would also be a good time for the Pakistan navy to build out tunnel complexes for its ships. Capping out ship sizes in the fleet to 6000 tons is smart considering where warfare is going; especially in a littoral context.
Btw, you are right about plans that look great on paper, but fail to achieve any traction. What maybe missing to get the ball rolling is the PAF and PN demonstrating active utility to its treaty ally Saudia and its partners the Kuwaitis and Qataris, it just the diplomatic efforts.
Has the PAF deployed any of its AWACS to Saudia? An awacs could keep an eye on projectiles coming towards Saudi infrastructure; a defensive move, and one to ensure the peace the diplomatic side is tying to hold together. If the PAF has 4 AWACS to spare, two could be assigned to northeastern Saudi and another pair could be assigned to the southwest. PAF JF-17 with laser guided rockets could be cued in to shoot down drones or cruise missiles.
If the PN is prepared, it could run the gauntlet with Saudi tankers in the Red Sea. This would bake in the PAF and PN roles as net security providers.
In return, the Saudis could put their leverage on the Afghan to knock off their behavior and come to terms for a comprehensive understanding, locking in the value of Gwadar and security of the Pakistani coast from blockade.