Old yishuv had high spiritual achievements, but their economic situation was dire. They were collecting for poor in EY all over Europe, whether poor or rich. I believe part of the lack of economic prospects was hostility of local population, limiting what and where Jews could do business.
If you do want to blame Zionists, I think a case can be made that they put priority on ideological land acquisition v. economic development. At some point in 20-30s, the donors wanted to spend money on developing Tel-Aviv into a manufacturing center that would create jobs and bring more people in. Instead, money were spent on kibutzim that were not economically productive.