If the company providing the service were financially liable for these blunders, they would be careful to select contractors that are capable of meeting the security needs.
As it is now, there is no financial incentive to select the "security aware" contractor, and the "non-aware" one is so much cheaper...
There is a good chance that the lure of security consultancy $ is resulting in a degradation of the quality of the applications.
Unless you're someone with specialized experience (crypto), you as a pentester are worth around $100k/yr. That's excellent money, but it's not the massive margin that would drive people away from webdev.
It will still be out there. For example, in a startup that's trying to get off the ground, going bankrupt because of security issues isn't that much different than going bankrupt because you failed to gain traction. It will still be put off to "later."
That said, with significant financial penalties there will be a point where the startup assesses the cost of security to be worth it (vs. now where there is no downside other than bad PR).
It's not a stretch that there should be laws that affect all companies that collect data on their users. I hope it happens soon! These companies should be paying quite a bit in fines for these mistakes, not just a few thousand for a bug bounty. Otherwise our personal information will most likely leak and be all over the web.