I'm just another gamer like all of you. That being said, I am a professional programmer
Do you know many well intentioned people wanted to make their own game before you? A billion trillion. Do you know many of those people actually took their project to completion? About 12.
I know a lot of projects that have tried and failed, and no offence but the teams were a lot more promising than any thrown together groups of enthusiasts. Probably the best example I could give you is a game called Dawntide, look it up. But here's a brief history of that game. There once was a guy called Wiz, he was an utterly exceptional programmer. He was one of the first people to make an EverQuest Emulator server, but unlike the other morons who made them with the ability to reach max level by typing in a command etc.. Wiz was smart enough to realize that being 'legit' was crucial. But he was also smart enough to make this server run great, and he modified the game in a way that actually even improved on the original EverQuest... It started to become extremely popular and word of mouth was really spreading. SoE got very angry and sent lawyers at him and things got very heavy for Wiz, he might be a wiz kid uber programmer and gaming guru, but he couldn't take on Sony. So he moved the hosting of the server to another country, he renamed it, and re-launched it with an entirely new world that Wiz created himself. EVERYTHING that was trade-markable by Sony, was replaced with something Wiz created himself. So places like The Oasis and Freeport could stay, but Qeynos, Iksar, and all the lore and all the gods had to be replaced, and Wiz did it, he also improved many of EQ's old mechanics and the result was a free alternative to EQ that many think is actually a better game. He reopened the game and this time Sony couldn't touch him. Legend has it, they then tried to hire him, and so did some other big companies, but Wiz being the eccentric strong minded nerd type, told them all to go fuck themselves. Meanwhile his server went from strength to strength, and is still playable today, several years later.
In the past few years Wiz retired from the server he created, and he handed over control to some trusted people. He then started his own company and took with him some of the best helpers he had from his emulator days. He secured funding, he bought a good engine, and work began with his new team officially, on a commercial sandbox MMO taking inspiration mostly from UO, but also EQ and some others. For the first year, everything was very exciting and things were progressing nicely. But eventually things went quiet, development ground to a halt, and months went by with no word. Eventually he admitted, they ran out of money and the project is on hold unless they can new funding. That was a year ago.
Game development is littered with stories very similar to this. Small budget is not less than a million anymore, when Vanguard cost at least 50 million and Rift cost at least 100 million, even 10 million is small budget. The fact is, the engine isn't even that important. It takes people to make a game, and people who work for free, can't be pushed to deliver and will end up drifting away because of family issues, personal issues, or their real job (that pays the bills) demands them. Games with teams like that rarely every get anywhere at all. If you have people who are paid a salary then you are talking say 50k a year for just one person. So even just one artist, one programmer, and one business manager type, that's $150,000 per year, and with just three people, you aint going to get much done in a year. It's more likely to take 2 years, so that's about a third of a million, and with no income coming from past projects, that money would have to be borrowed from somewhere. And people don't invest a third of a million on something that might not work out.
It's not impossible for something like this to work, but it's literally one in a million. The best chance is to do something like Minecraft. Just have one guy working 24/7 because he a poopsocker who lives in the mountains, and make the whole thing in java or some crap. The result will look like something from the 1980's, but it could have some decent gameplay. Release it on your own website so no assholes take a cut, and you could make some money, maybe. But only if the stars align and you sell your soul or something and end up with other people generating hype about your shitty product, again, like Minecraft.