Responsive websites consist of much more than a well-sized backend and fast service response times. Our modern web applications provide rich content in order to attract a broad user community. The navigation needs to be as easy as possible and the sites must support many devices such as mobiles, tablets as well as desktop computers.
With perfect user experience in mind, web developers often use rich frameworks, which allow them to create fancy user interfaces. In addition, every engineer comes up with their favourite framework and integrates this into their new web-based business applications.
I understand those developers, but the problem might be that the webpage loads slowly due to having too many resources that need to be downloaded. Therefore, my personal recommendation to avoid such issues is twofold:
A lead developer or architecture specialist should provide strict policies and regularly verify the used frameworks.
Web page design analysis should become part of your software development process to avoid major web page design faults.
So, keep web performance best practices in mind and avoid critical design mistakes. There are excellent tools such as PageSpeed or YSlow available for free. Use those tools during software development stages and verify the score of your application regularly.