The shortest answer to that is - yes. Sadly it is a fact that one of the fastest evolving industries in the world is digital.
What that means is that things are changing, improving and superseding existing platforms at such a rapid rate that what worked 3 years ago does not work anymore, purely due to the fact that systems have upgraded so many time and with so much improvement to many features that your existing website has become a digital fossil in almost the blink of an eye.
However, there are ways for you as the owner of that website to extend the life and to put the website is such good shape that when you do have to migrate to the newest platform, that it is as painless as possible and that it had the smallest impact to the over-all ranking of your website and content.
So, you have heard it many times and you probably already know that you should be updating your content, that you should have work done to ensure that all the bells and whistles are working and working the best they can for the platform that you have.
Along with this it is important to ensure that your search engine optimisation is kept up to date as this will pick up and correct a lot of issues that crop up continually with a website and its performance. With these issues sorted and kept up-to-date it means that your current site will perform better in searches, will last longer before it reaches the end of its usable life and will also then provide you with a valuable platform that you can migrate to your new website so that you don’t loose forward momentum and any temporary loss of ranking from switching to a new site, is regained quickly.
So factor in that you do need to keep working on your current site, and that it will need to be fully replaced within 5 years. It’s just the nature of how the internet is evolving.
Just like trying to use the flip-phones from 1995, it ain’t going to work.