I think that too much investment could result in more noise in the field. First of all because it will result in large number of published materials, which could exceed capacity of other researchers to read it. In result really interesting works will be not read. It will also attract in the field more people than actually clever and dedicated people exist. If we have 100 trained ai safety reserchers, which is overestimation , and we hire 1000 people, than real reasesrchers will be dissolved. In some fields like nanotech overinvestment result even in expel of original reaserchers because they prevent less educated ones to spent money as they want. But most dangerous thing is creating of many incomparable theories of friendliness, and even AIs based on them which would result in AI wars and extinction.