Responsiveness lets you target two platforms with shit UIs for the price of one good one*, which is what businesses want[0], per the good ol' "worse is better".

* - two for one up front, ongoing development and maintenance costs of modern responsive UIs is going to be much greater than doing things right 2 or 3 times, but those costs are beyond the next sprint, and pay the good chunk of salaries in this industry, so...

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[0] - And, unfortunately, this thinking became the zeitgeist of software development, so OSS projects do the same.