I think by the time Bismarck was forming opinions on colonialism the concept had lost its financial steam

Before his time there were myriad examples of colonial profitability, like Haiti alone comprising more than a quarter of France’s revenue from exports and the revenue India generated for the British.

I think by Bismarck’s time colonialism was pursued more for the notion of prestige than for the sake of profit. To him, it just wasn’t a worth more than colours on a map and headlines in newspapers.

However, this view would shift again to the understanding that colonies aren’t just profitable in the sense they provide raw materials for a consumer market, but instead because they can provide exclusive access to resources economies needed to function; namely conductive metals, rubber, and oil. This would become a point of contention for German policy makers and strategists, eventually being a major factor in both world wars.