http://www.gamasutra.com/blogs/AlexNichiporchik/20151106/258662/Dont_develop_games_fulltime.php
Well written article, and while being a very personal opinion of the author, does raise a lot of points people like the OP should take into account.
Why put everything on one card and quit your day job when you have the luxury of a job paying your bills while you learn a new trade and do the first initial trial-and-error experiments?
Does it suck to work two jobs and have little free time left? Yes, it does, even if one of those jobs is a "labour of love" thing. Will it considerably slow down work on your games when you can only spend 20 hours a week on it even with all free time spent on it? Of course it will.
On the other hand, getting into debt because you play the Indie-Dev-Roulette for too long without hitting the Jackpot sucks just as much. Depending on how you handle different types of stress, it might actually be MORE stressfull to work on it fulltime, instead of working two jobs with little free time left. In the second case at least you know you will be able to pay the bills at the end of the month.
A lot of Indies seem to take on paid gigs and freelancing works to support development of their own games. Granted, that might be related work that brings them valuable expierience they can also use for their own development. But the net effect is the same, these paid gigs tend to slow down development of their own games considerably.
I will not go into the "can a lone Indie survive on games" discussion... I have little personal expierience with that, and I still don't know if I ever will.
Point is, you shouldn't have to ask the question. If you aren't already able to live off your own games, don't gamble on it... I know some people think it is necessary to starve as a start up to make it big. It is possible they are right, that a second job will always slow you down.
But, we are talking about a high risk business where even earning 500$ a month seems to be a rarity... this article on gamasutra tries to prove this "Myth" wrong, but when you compare the numbers it presents to the total of games submitted to the app stores, the sad reality is still that most game devs must be way below it:
http://www.gamasutra.com/blogs/MartinMacmillan/20151106/258718/The_Millionaires_Index.php
45161 devs made 500$ per month or more... including non-game apps. How many devs did release apps in this timespan? How many have given up their app development in this timespan?
TL;DR:
Don't give up hope yet, but don't - ever - quit - your - job - without - a - paying - alternative.
The story of the starving artist doing whatever he wants sound attractive until you are the starving artist yourself. Build your games and your business in your free time, show your devotion by moonlighting. Maybe find a better paying or better suited day job if you can (going part time is a good idea if it still pays enough).
And cut the cords to your day job when you are damn sure you hit the motherload, not when you THINK you could hit the motherload in the near future. Debts are no joke, and the stress of having a badly paid, boring or awful day job is not comparable with a struggle for survival when your plan doesn't work out in time.
[snipped]
What you can take from this is learn to actually create the apps first. If you can't program you are off to a no starter.
Buy in assets. You can buy complete game asset sets from sites like GraphicRiver for around $100.
Don't aim to make waves, the extra effort is not worth it.
You need to have several games making you money before you start to see a return on investment.
While I see where you are coming from, and would support the "many games" strategy especially for the mobile sector where average price per game has been raced to the bottom, "mediocre" games do not sound like a good strategy long term. Maybe not even short term.
It is certainly a way to get you started and get the needed expieirence in finishing and releasing a product. But there are literally millions of mediocre games on the app stores already. How many downloads can you expect from a mediocre game? How big is your chance to hit the discoverability jackpot?
While I do think spending too much time and effort on building assets is a dumb idea for a lone dev, especially if aiming for a quick RoI (you can do that if you are a hobbyist spending years developing your games), I would be careful when buying stock art. If something looks good and sells at a good price, many other game devs will use it too... your mediocre game now has also mediocre assets, it looks and plays like dozens of other games on the app store. How do you stand out against this competition?
If the answer is "don't even try", what do you do when somebody DOES try and is successfull, now attracting all the money that is spent on this genre and platform?
There is always someone doing things better, being able to invest more money and having more luck. But instead of aiming at the biggest market with the least effort and trying to pick up enough breadcrumbs the big hitters leave behind to survive, aiming for underserved niches and trying to find a community is a better long term strategy for an Indie dev IMO.
In the end your plan sounds too much like "fill out the lottery ticket and hope for the best" to me at least... only that you spend a month, maybe two filling out the lottery ticket, and maybe even spend multiple 100$ worth in assets and tech on it.