More and more IP cameras can't be set up without a phone app. TP-Link's Tapo line is really bad about it. Even some Reolink cameras can't be setup on their own.
Now that high quality, affordable brands like Dahua got banned (w/o evidence), there's less pressure on the survivors to not be awful.
More evidence that this isn't about cost at all, but control. Fortunately, the good old-fashioned "dumb" ones that just have a tiny web server to serve their configuration and viewing UI still exist, seemingly at both the ultra-cheap (unbranded/random brand ones from China based on a reference design, built by companies with no desire to host anything) and ultra-expensive (Axis, Bosch, etc.) ends of the market; the middle is entirely filled with the "smart" "cloud" crap.
You are absolutely correct. However, in regards to a phone app there is likely to be 2ndary pressure from data brokers who firehose cash for any data their phone app collects.
I just installed 10 Reolinks and I had to set up a phone app for two of them that didn't have an Ethernet connector. Ick.
I have one Tapo and ran their app from an android emulator. I won't buy another.
The company doesn't have to go away, the app just has to have issues. At least with web apps, you aren't depending on the manufacturer investing in nearly continuous upgrades to work in the rapidly changing phone environment
A web UI will continue to work for decades. And app will likely not last a year without updates.
They basically are. They just license their name out now, it’s like buying a Kodak router.
(That’s actually relatively common with various tech-adjacent companies, e.g. off the top of my head both Energizer and Philips license out their brand to third parties for random crap, even though they make actual products themselves too.)