Licensing the patents worked but it's also worth looking at Tesla's relationship with George Westinghouse who became a patron more than an investor.
What's the avenue for a Nikola Tesla today?
Not sure you want to end up like Tesla. He died broke and alone. I wouldn't try to emulate his avenue, only his genius... If such a thing is possible.
Generally fundamental infrastructure improvements are very very hard for the individual contributor to capitalize on. Part of that is because there are usually alternatives for everything so its pre-commoditized and thus hard to extract value from, and partly because the legacy of 20th century was rent seeking businesses which polluted the waters for everyone.
And his patents were detailed, precise, and often accompanied by a model.