Dont think that there is really a problem. On the contrary I prefer systems such as stellar XLM, where every vote is openly bought, to EOS where there is a constitution stating votes 'should' not be bought. And then there are some non-public deals made in the dark. Because people will do them, the question is just if you can see them.

But I also agree with Vitalik. If you use POW this whole issue does not exists in the first place. POS or dPOS does have some potential especially in scaling, but it also has some serious disadvantages compared to POW.