Because creating cross platform apps has always been really difficult. And creating web pages that work cross platform is less difficult. If your objection is

Because creating cross platform apps has always been really difficult. And creating web pages that work cross platform is less difficult. If your objection is that it's inefficient and sometimes leads to bad quality output, I'd agree. But it's the option with the least friction so people gravitate towards it, we might as well make it work better.