Why does the app not ever work?

No information we users can look into to try and help you so I’ll assume you are just unhappy, not seeking help.

As this is a user to user community, with minimal Sonos presence you might address your complaint to Sonos Support.

Your post suggests you tried the same course of action each time, with the same outcome each time. 
Is it time to try an alternative approach to try and resolve the problem?

ok, I’ll give some details. Now I’m having an issue with the app not seeing my system with all my speakers connected to it, saying that there is a wifi problem. I’ve reset the router and modem. Also, done the recommended factory reset of the speakers which had to be added to a new system. Then, it worked. 

1 day later, same problem. There is some sort of wifi update that needs to happen but keeps bombing out saying it can’t be completed. That’s for the play 1 speakers. My sonos beam soundbar is dead without the update that I can never get to work unless I plug it into an ARC HDMI port on the back of my TV. 

Basically, how do I keep these things updated without dropping from my system and being unusable whenever there is an update that the speakers need?

Every time I have to do a factory reset to a simple speaker, it makes me think why they didn’t just bring back the old app until the new one was better tested. 

Nobody should be resetting their Sonos.  It doesn't do anything a simple reboot won't do, and it erases important dignostic data.  See link for more:

https://en.community.sonos.com/speakers-229128/factory-reset-what-you-need-to-know-6832540

First question: who recommended a factory reset? 

Second: is your system fully updated? You’ll need all versions of the app and all speakers to be on the same revision. It can help to temporarily wire a speaker if you’re having problems updating via wifi. 

Third: if you restart your router and modem you should restart your speakers too - ip address conflicts are a common issue otherwise. Power down everything, then restart modem. When it’s fully running, restart wifi. When it’s fully running, start speakers one at a time. Start any surround speakers after the soundbar. 

If the simple restart everything doesn't work you can assign static/ reserved IP addresses to all Sonos followed by another power down all Sonos, reboot router and controller then powering the Sonos back on.

It might not be your main problem but it is a common and hard to diagnose one, best to eliminate it to make finding other issues easier.

See your router's DHCP Settings page for instructions on setting addresses.

Agreed; that was going to be my next suggestion. It might explain why the system works for a day and then plays up, as outlined by ​@kal12345 in an earlier post. 

​@kal12345 

At this point, please stop arbitrarily resetting things. Tell us about your network. 

• Are you using your own router or one provided by your ISP?
• If provided by your ISP are the router and modem combined into one unit or are they separate?
• Is your network comprised of a single router or is it a mesh network with a router and one or two satellites? 
• What are the brand names and model numbers of your network gear (such as  Netgear, Linksys, TP-Link etc.).

I have my own modem (surfboard 1 gig ) so pretty good, also a nighthawk router that is also pretty decent but can’t remember the model. But they are connected with cat 6 no mesh router just the one unit in the middle of the house. There are no issues with other devices in the house. However, I did have to reset the cache recently on my router due to a service upgrade. That might have disrupted the sonos settings. 

Below are the factory reset messages I get from the app.