You seem to be forgetting the KC-10s (now also Boeing) and the KC-767ATs delivered. And your ignoring of the intervening years of maintenance and support is rather dishonest.
What was especially devastating to EADs was their inability to commit to a two year time line to stand up a support system. Boeing had no problem.
That was the previous US Tanker competition that Boeing lost, that time to McDonnell-Douglas. It was MD that designed and built the KC-10's boom, thereby shooting down the myth that "only Boeing" can build a boom.
Going all the way back to the initial KC-135 purchase, Boeing has never won a US tanker competition. The KC-135 was sole sourced, and Boeing lost the ACTA competition to MD and their KC-10.
The KC-10 was not a Boeing design. They bought the rights to it when they merged with MD.
And there has not been a single KC-767AT delivered because the KC-767AT doesn’t even exist yet.
Maintenance and support is not the same as BUILDING tankers.
No, Boeing has a problem with delivering aircraft on time. Maybe if there wasn’t a 2+ year delay then they’d MAYBE have more than just 2 customers.