China has the largest reserves. Only a fool would decline Chinese investment. Of course the modalities have to be worked out, but everyone knows where the cash is.
It is funny the West lectures us about the dangers of trading and cooperating with "evil" China when the biggest lenders are Western nations and institutes themselves. Today many nations have put all of their eggs in one basket which is the Western basket.
Who says that other nations aren't interested in Chinese FDI? China is already investing in many other nations around the world. Pakistan is just one nation.
Secondly you are putting your eggs in one basket. The Western nations all have a similar business model. In fact the whole system is essentially collectively one. America dictates this economic system. If the Americans say A it is A. All other Western nations follow the dictation. That is hardly an independent system.
BD is not putting all it's eggs on the Western system.
It's export to non-Western countries is rising quicker than to the West.
Pakistan clearly has one option and that is China - bad for Pakistani independence over the long run.