My Lyft driver from LAX to DL last month, told me this. He said that international visitors must use Uber, as it is international and accepts their CC, lets them have an account. Lyft is US only, you need a US CC to have an account. He said this is why from airport Uber is often in Surge pricing (high demand) vs. Lyft. For me, Uber was almost $60 more than Lyft, LAX to DL. This could also have an impact (lesser but possible) at WDW.
If this driver was misinformed, I apologize, he drove for both companies.