If this was true then every startup would be a success. You need a lot more than that. Not to mention that finding a problem that costs a company $4k/mo and coming up with an elegant solution is a lot harder than it sounds.
Many first time founders think exactly like this. They're blindsided after the product is built and they realize the hard work has just begun.
I cannot name the online system we use, but I am willing to say that page load times average 15-30 seconds. The interface is riddled with bugs. There is no customer support for what I imagine is a $5k/mo meal ticket. They also hotlink all of their JavaScript.
Functionality is easier to sell than all of the other facets of the start up. CIO wants to know if the system will replace it. CEO wants to know how much money it will save. Higher level execs want to be able to export it to Excel and easily notify mid level execs when they are behind.
Once again, I kid you not. This expensive app is literally a spreadsheet with dynamic columns which allow administrators (dept heads) to assign values. The hierarchy is the system is sys admin, admins (officers), users, and temps.
Job scheduling, accounting/vouchers, log analyzers, time management, project management, supply systems, commissions systems. If you have seen them once, you can probably reproduce it 'with a twist'.
Life of the corporate drone. And yet... in exchange for forfeited dreams and ambitions you get a nearly assured nice retirement someday and little need to think or work hard.
I hear this a lot, but are there numbers on how many people are managing it? I.e. if you exclude apps put out by large companies, how many people are earning $5k+/mo off Android apps? I don't even have a ballpark guess; is it 10 people? 10,000 people?
It has the potential to make $5-17/day. I'm guessing if I corrected/updated the code, it would jump in rank. If I could generate 13-15 apps that fit into this type of niche, I would easily reach $5k/month with lazy/horrible coding. If I just sat there for one-two full month(s) churning out one app a day, I would probably be able to reach that goal.
$150/month product that saves businesses $4,000/mo (one less programmer). Hard part: Find 70 clients.
Working in industry, we demo products all the time. We pay outrageous amounts of money for an online time tracker which is basically an online spreadsheet. We have considered obtaining systems for managing accounting, supply, etc.
Focusing on our core business, policies, we never get tied up in 2-3 month/year adventures in uncomfortable territory. There is no innovation, just maintenance. We use a 20 year old 4GL language assisted by native Python/C.
I could crank out Android apps in niches, write web content and advertise, build a few cloud based web products (CAN IT EXPORT TO EXCEL!?!?!!!111), and easily live off of 15-20k a month with huge fluctuations (both directions). I choose the simple life of industry.
Not to mention, it is so hard to motivate yourself to go from start to end on a product. Most of that energy was used in my late teens.
Right now, I could be cranking out that turn based strategy Google Glass native app, because native apps with delays in turn taking are going to be the key to Glass (it gets hot!). Instead, I'll just build another fixed width extract with this day. It will run in 1/16th of the time of the original. People will not notice or care until it breaks again. Ad absurdum.
I suppose its worth mentioning, I know a few who pull in 4-6k a month solely on advertising/affiliates. Completely passive, they have months worth of posts automated to go out every 2nd or 4th week. I've pulled off 1-2k using the same method, but I always had a hard time finding microniches that were available for me to dominate. Writing about en pointe ballet, dremels, silver polishing, simms fishing gear etc. is not my ideal goal. It did make money though.