The point I think is this: if topological qubits are similar to other types of qubits, then investing in them is going to be disappointing because the other approaches have so much more work put into them.

So, he is saying that this approach will only pay off if topological qubits are a fundamentally better approach than the others being tried. If they turn out to be, say, merely twice as good as trapped ion qubits, they'll still only get to the achievements of current trapped ion designs with another, say, 10-15 years of continued investment.