Chrome has the biggest market share (outside of iOS) because it has the more features (that is web APIs) and less bugs, making it the most reliable browser. It is very common to encounter websites or applications which do not work properly in Safari, and web companies and developers are encouraging users to use Chrome because of that.

Here is a rather exhaustive list of all the features that Safari is lacking and which prevent the development of web applications that could compete with native ones: https://infrequently.org/2021/04/progress-delayed/

A lot of companies are deprived access to iOS users because they don't have the financial means to develop applications specifically for iOS. A lot of companies which have the means to develop natives applications have to compromise on the features they develop because development cost is much higher. A lot of companies are losing money because they have to use the app store and give Apple 30% of their revenue while they could use web applications instead and use payment solutions taking less than 5% of commission.

Because of Apple anti-competitive behaviour, iOS users are deprived of applications that just can't exist, deprived of features that companies can't afford to develop because of the high cost of iOS specific development, deprived of applications that could be of better quality if the developers behind it could focus on one codebase, and deprived of cheaper applications and in-app purchases.

They are deprived of the benefit of competition, basically.