Let’s start with the biggest changes internet has experienced.
Strong response to new web standards
A decade ago, a lot of people were still using slow browsers like internet explorer. Internet explorer was based on old tech infrastructure, so website-specific languages like HTML and CSS could not move forward. Some websites did modernize, but they had to also develop alternate versions of their websites for those who used old browsers. Internet Explorer and similar browsers could not support many new features present in newer versions (CSS3 and HTML5).
Improvements in UX
This is related to the previous point. These days, more and more browsers support HTML and CSS features that improve user experience. Flexbox and grid systems make it easy to design the web application layout for example. It is also easier to build responsive web applications. Because most web apps are viewed on phones today, this makes a big difference.
10 years ago, it was nearly impossible to browse internet on your phone. Now almost every theme and CMS tool builds beautiful websites optimized for mobiles.
Emergence of no-code
Content management systems (CMS) have always existed. WordPress was no less popular a decade ago than it is today. WordPress websites have become more beautiful, and have basic dynamic features. Mostly they are used for creating blog websites.
However, one big change is the emergence of no-code services. These tools allow you to build web apps with much wider functionality than simple WordPress blogs. There are plenty of tools that do not require a programming knowledge for building various types of applications. Even for developing mobile apps. Shopify has created a solution for building ecommerce websites, for example.
As a result, now everyone has access to building fairly complex web applications. It takes less time to build a simple prototype or even an MVP.