At the federal level for president that is certainly true.
But for all other offices they have just as much chance of getting funding as any other candidate mischievous that innovate it's just that they don't get as much because not that many people align with their political views

I ran for Congress in 2016 and had to collect a 1000 signatures minimum to get on the ballot as did my Republican incumbent opponent. Meanwhile the green party and libertarian candidates merely had to be nominated at their state convention

I actually favor public funding of candidates in the general election equally and banning any outside money being spent by those candidates candidates but I don't believe it's true to say they don't have an opportunity to run get on the ballot or even win
They do not have the support