what brings economy down is base on focusing on one particular thing not be diversified in different sectors, so when that particular product fails to trend in market the way it's before such country will be shortage of economy
This is evident in Nigeria, prior to the discovery of oil (in 1953) agriculture was the main driver of the economy contributing hugely (more than half) to GDP growth and also export revenue.
The quest to discover oil in Nigeria began at the turn of the century and was very expensive, after it was discovered in 1953 in non-commercial quantities, over £6 million (£123 million in today's rate) had been spent on the quest, hence more effort and resources were engaged to accelerate the discovery of oil in commercial quantities, inorder to recover the lost funds, this was achieved few years later. After this, efforts were hastened to begin exploration later in that decade.
During all this, agriculture which was the was the core of the economy was beginning to be neglected and it's contributions to GDP growth began to drop, export revenue accrued from it was hit harder, as all efforts shifted to the liquid gold.
The discovery of oil however did not rescue the economy as many thought it would, mismanagement of the oil industry led to conflict in the oil producing states as the indigenes clamoured for better revenue to their zone. The oil drilling exercise destroyed the environment and fish market which was the main source of income among the locals was crippled due to oil spills. Conflict and militancy slowed down oil production and was a menace for many years. The agricultural industry was thus double affected by the discovery of oil as lands and vaible waters in those regions were lost.
Fast forward to today, agriculture barely contributes 5% to national export revenue, and the country's inflation index has spiked from the period before the discovery of oil to today reaching a height of about 2000%.
Crude oil failed to boost the economy due to mismanagement and corruption and the lack of attention to agriculture meant there was no diversification.
With the Advent of electric cars and the quest for safer and renewable sources of energy which doesn't harn the environment, the oil market would likely drop in the next half a century, adversely affecting economies which are over reliant on it.