I don't think that the next 10 years they will reduce fees because of the inflation as well as the cost of living is increasing yearly. Instead of saying that ebay/paypal will have a reduction for the fees they've got, they will probably improve their service and that will be charged to their consumers, including me and you.
And it is also possible that these companies will accept bitcoin soon. Since people will look for some other options to make them save a lot of money with the same services, I'm sure that they are keeping an eye for adoption of bitcoin. They might not doing it now but that is also a possible thing in the future when their sales are cut down to half.
If the bitcoin price rises to certain level, they will adopt it.
They wont accept bitcoin as part on their company because if they do that revenue would really be lessen since they could not impose taxes on it.