Sure! I've actually created and sold a tech startup and helped tons of indie devs.
Can someone theoretically make it as a solo dev? Sure. Whether or not being an indie dev is viable for YOU is the real question.
1) Indie Dev == Running a Business
So, the first thing to keep in mind is that being a dev involves a completely different skillset from running a business. Some people are happy doing both, some hate it.
A game studio - whether a whole team or just 1 person - still has certain requirements. Marketing, Accounting/Taxes, and Handling Legal Contracts are all a part of any business. When it comes to making a game, you have game programming, game design, art & animation, UI/UX design, sound effects, music... There are those rare people out there who have all these skills, but most people will have to hire, subcontract, or pay for pre-existing items. That requires recruitment, knowing local/state/federal laws, and managing payments. (For example, California's new "AB5" law turned a lot of freelancers into employees who are entitled to full benefits.) At the VERY least, you should work with a lawyer to ensure you aren't breaking any laws. I also recommend using an outside accountant.
2) Know Your Audience
Old business adage: If you are making a product "for everyone", you are making a product for NO ONE.
Even professional studios sometimes drop the ball on this. You have to know who your target audience is, how to reach them, and what will attract them to your game. If you wouldn't play your own game, you probably won't know enough about target audience to reach them. (This is why diversity is so important.)
Also, understand the state of the market you are targeting. If it is too saturated, you'll need to work harder to stand out from the crowd. This is why a lot of people get discouraged and think they "can't" succeed. You aren't going to succeed as a solo indie if you are directly competing with Disney/Activision/EA/Tencent. This is why I highly recommend you stay on top of industry business news (not just gamer news). Most of us rely on www.gamasutra.com to see what business deals and trends are happening. The key to any business's success is identifying a significant and underserved market.
3) Manage Your Schedule
It is easy to fall behind and get discouraged while working solo. Create a schedule and milestone list. This will help you to stay focused when you REALLY don't want to work on your project anymore.
4) Test, Test, TEST!
Get as many people as possible to try your game on as many of your target systems as possible. I had a colleague joke once that when we launched we'd discover that our game didn't work on computers that were grey. It was a joke on the fact that post-launch you will find your game breaks in the most bizarre ways and times.
Also remember that you are the expert of your own game, others aren't. They will play in ways you have never considered. Games are a form of communication, so you won't know if you are communicating correctly until people with 0 knowledge of your game try it for the first time. (As soon as they have tried it or had it explained to them in any way, they are "tainted" as a "fresh" playtester. So don't tell them anything on their first playthrough and get as many people as possible to be "fresh" playtesters.
Final Note:
Not knowing your personal background, this is just a collection of some of the most common points people need to learn. I'm happy to answer more specific questions if you have any.