Hello, What is the importance of onpage and offpage optimization recently ( may be in less than an year time) ?. one of my webpages is step by step decreased from page 1 to now page 2 SERP position 15 in last 3 months . I am sure it will continue decreasing more. Google found the content good till 3 months back ( it put the page in page 1 SERP 4 or 5 ). But have for some reason pushing it down. The content is 100% original. There is not any updates to that page. PS: I think you can come page 1 with nice content without any kind of optimization.
I don't think that the importance of these factors decreased these days. Onpage optimization is still very important because the main aim for Google is to show relevant content, so content and what's around is of high value. Also I haven't seen any signs that offpage optimization has become a smaller factor for rankings. Try to consider a bunch of factors when analyzing your ranking drops. Also remember that rankings depend not only on your website but also on the pages that are included into the SERP. They change, appear and disappear, so, say, some new websites appeared and their factors are better than yours, you may be dropped to several positions, and this is not because onpage optimization lost some of its value.
Always On page optimization importance's are increasing. According to recently Google updates you need to update relevant Meta tags on your website.