They never built anything on loans, in fact never built anything. They always had only primary and proto-industrial sectors like Bangladesh whose low base effect gave them temporary growth. Neither of Pak or BD ever bothered to diversify economic portfolio.
Every country transits from low end to high end, those who don't get stagnated.
en.m.wikipedia.org
Given that Bangladesh suffers same drawbacks even at low TFR than Pak. It's financial problems will be bigger. Though, it will be in a middle income trap and not a low income trap like Pak given it has better scores in factors of international relations, spending on infrastructure instead of military and terrorism, finally FATF sanctions.