(The 747 was designed when we had little to no history on jet engines in commercial service)
And ..... the B747-400, weren't B767 & A310 ER's in existence by then?
(Smart people don't use 4 engines when they build aircraft)
So what about the BAe146, the DHC7, many militaries etc. I guess only Douglas built good airliners, ones with less than 4 engines that is (post DC8 era), but then some tin-can manufacturer put them out of existence!