GDPR and Apps

I got a ton of emails these days from websites I use. They seem to be panicking to violate the GDPR. Seemingly they tried to comply by sending out emails which is probably complete nonsense.

Anyhow, what I find strange is that I got zero of these emails/messages regarding the apps I use. I'm sure apps are covered by the GDPR just like websites.

Why didn't the authors of apps take similar steps? They probably cannot email me because they do not have my email. But couldn't they pop up a dialog or remove their app from the app store or block european users just like some websites did? Why do app authors behave so different?

Or is it because apps are not phoning home so much / don't have as many embedded 3rd party code that phones home to 3rd parties?