My understanding (via astronomer scuttlebutt) is that the SETI institute fell massively short of the private fundraising goals it set at the outset of the project. (In fairness, this was during the economic crisis.) Paul Allen's funds were intended to start the hardware off, and then the privately raised funds would yield the operational/expansion budget.

So, not so much mismanagement as overoptimistic budgeting.

(Building a few telescopes at a time is likely a false economy, given the costs of paying engineering/fabrication costs over a longer period.)

All that said, it's going to be harder to get private donors to contribute towards telescopes in the future...