I think that can be a bit of an issue you can't get around though completely regardless of what OS you're using. If you have a company that sells a tremendous amount of phones then I'm guessing it'll be more likely that you're getting a phone that just off whatever "manufacturing line" the company uses more recently. And with more recent construction etc I'm also guessing the manufacturer will have had time to update the OS. So in other words, if MS produced X amount of phones and sold fewer than expected, then when we're buying them much later there's more for the phone to update.
So I think that's a two-sided coin in that first of all MS said it's treating W10 as a service, where we're getting more frequent updates that include more features rather than fewer larger updates, and so along with that comes more volume in the actual updates. That's a bad thing if the phone has a lot of catching up to do, but it's a good thing once you're caught up assuming the updates are solid, because you get frequent security updates, bug fixes and new features.
When I got my Lumia 950 it took a while to get it up to date, but once it was updated it's been more than fine, and it's gotten better with each update.
And for the future the incremental updates should alleviate this, if I understand it correctly.
It has nothing to do with the amount of updates but rather how they are implemented, MS approach is severely flawed, time consuming, and requiring way too much intervention from the user. Never thought I'd see a day when their phones took on the same traits as PCs but it has.
Initial setup and applying 1 update should not take 2+ hours. This
DOES NOT include one iota of personalization like tweaking settings, adding accounts, installing our own apps and so on, you know, the part that you'd think would take the longest but of course that is personal taste dependant. In the midst of all that you're constantly notified and required to do so... "your language was just updated, a restart is required", "Glance was just updated, a restart is required", blah blah blah. Sorry, to me that is not advancements in technology in that the process should become faster, more fluid and less painless for the user, MS obviously missed that memo.
Then we get to the store, yup the store. Updating
JUST the pre-installed apps, for me, took several interventions just to get the ball rolling. It took forever for the downloads to initiate, forever to complete, then with more time being spend intervening again because errors during the download process were encountered.
Been through above scenarios with WP/WM enough times to know it is not a one-off affair and not relegated to just my part of the world.
Then we compare our old 650 to the new, same builds with only 27 days separating the two, apps that
WERE there are no longer and settings menu
IS NOT the same. Goes for my 830 running
SAME build, different in many ways including areas described. That's what I mean about consistency, MS can't keep things on an even keel which really can be frustrating at times. Just as they "changed direction" in regards to the platform/OS they continue to do so on a regular basis at every turn, that to me indicates they haven't a clue what direction they are headed in.