I can not remember Bigpants to have claimed that aircraft have become less safe... (neither did I)
The accident rate of course is not only related to aircraft design and production quality, there are so many more factors to be considered.
The point is not about safety, it is about all these little glitches and flaws that require constant attention. You should show the rate of structrures related airworthiness directives, mandatory one time inspections and retrofits for comparison. Our whole aviation system has become much more failure tolerant, this does not mean that any single aspect has improved, we can only accept more issues today without having a real problem.