Well I am not sure what is the strategy. Because I have heard a rumor that military always control the government from behind.
You see this govt is ruling even after an election that is technically un acceptable in democracy?
Previous bnp govt was actually looting country, corruption was everywhere specially in power supply, and even when buying military stuff.
And military must not tolerate that so they are backing the current govt.
Otherwise you must know that after 15 January 1996 election bnp survived only few days but not situation is different.
How ever to answer you question must admit that Bangladesh politicians are hypocrites greedy, and actually rotten (both awami league and BNP ).
So they bought outdated weapon to be beneficial from army budgets and they have paid the price.