You'd have to have a real lock on it to get anybody but a shady lawyer to take it on. It's very unlikely that you'd be able to do that under almost any circumstance. Yes, the potential payout would be large, but the expenses the law firm would have to pay in the meantime, and carry for the many years it would take for the lawsuit to come to a conclusion, would also be very large.

It would be a huge gamble and reputable law firms would have to feel extremely confident that they wouldn't end up on the losing side. That's a big ask regardless of how good you case is. These tech companies have enormous warchests, can drag these things out essentially forever, and the odds they'll find a technicality that would blunt the lawsuit are very high.