True. A web developer has to keep the on-page activities in his finger tips. If he's not aware of the periodical changes, he might repeat some of the steps that have already been tried and tested. Not only will he complicate things for future developers, he might end up playing with the search engine rank of the website.

The On-page optimization somewhere depends on web developers also, as if the website is designed as per the SEO parameters then there will be less scope of any changes in the future for search engine purpose.

As technology advances and web usage evolves, so do SEO best practices. Web designers now have more choices and technologies available than ever before. As we enter 2014, I expect we will continue to see advances in web design that bring even more options.

Nice question, Actually When I read first time then I don't understand your question mean. But this is fact that if web developer will develop an seo friendly website then there is no need to correction in Future. When developer developing a website for their clients than your clients wants perfect work. So if you create seo friendly website then you can save your future time to correct all seo issues.

Web Developer performs and use the On-Page Seo Activity of the website that promote ranks and increase traffic on it.