You are the kind of person who believes that every app should support ie8 and even before that, right? Don't forget to limit your 500ps car to drive only 25mph...
That's true, in most of the company's I worked (includes the current one) I'm not interested in the product at all. I work there because I can decide which tech stack we use, try and learn the fancy stuff and have some fun building it. Why? Because I can - I am one of the few "good" dev's out there. So many companies are hiring and they take what they can get. And I as a dev can choose where I want to work. And of course I choose the interesting one. In conclusion there are much more companies hiring then good dev's looking for a job. So the company has to make itself interesting for dev's.
But I don't think that's bad at all. With modern devices and Browsers you can't tell the difference between using a framework or not.
Don't forget that a dev may need another job in the future. And it doesn't help finding one when spending the last 2 years building an app with some "oldschool" tech stack that performs well. Most companies are looking for dev's who worked with the cool fancy stuff like react because that's already the tech stack they are using.
And what is so bad trying to make my job interesting? If it's boring I wouldn't care much about the end result. Just another 9 to 5 job then.
Believe me when I say that I have had hundreds of meetings where I tried to tell them that what they want is crap. But in the end it's their decision not mine. And in the end I have to make money so I build what they want. This has nothing to with me being unprofessional.