1) I dont dispute your experience.
Just pointed out it isnt the experience of others so doesnt seem typical of Viking.
2) so you pre paid gratuities thinking that gave you preferential or superior service to others.
No it doesnt work that way and that isnt why most people pre-pay them
Your sentence after that doesnt really make sense to me.
Yes I would pre pay them purely for convenience - indeed that is what I do, I go on gratuities included i n the price, for convenience, or pre pay them at beginning of a trip (eg Wendy Wu tours, you pay tips in local cash at beginning of trip)
3) yes, possibly was a newer crew, possibly needed more training.
But the level of service would be the same, whether poor service or excellent service, - pre paying tips does not get you any better service than anyone else.