There's quite a few more monitors than two.
Start here.
You're right that there are more choices than there used to be. Give it another 6 months and more of the objections will probably have gone away - and, hopefully, there will also be a decent choice of TB3 docks.
However, I'd point out that those are all USB-C which means that a 4k@60Hz display will snarf all four of USB-C's high speed data lanes, so all the downstream USB ports will be USB C only... so, as a single-wire dock, OK for your mouse and keyboard - not so good for 1G ethernet and backup drives. Also, I think the jury is still out on whether 60W is enough for a 15" MBP (if 60W is 'good enough' why do Apple - who are too tight to even bundle a new charge cable and extension cord if you buy an extra charger - bundle an 87W charger?)
USB-A and Ethernet ($20)
..."Out of stock"
DisplayPort ($14)
...Actually, I need MiniDP socket for the LED Cinema display at work (a decent display which isn't getting upgraded any time soon - I've succumbed to using my own laptop, but bringing my own display is a bit much),
When I was looking last year, there was one USB-C to MiniDP socket available on Amazon which had a slew of "avoid - does not work" reviews.
This looks OK and, today, finally seems to be available (it hasn't been in the past).
All Legacy Video ($20)
...again, a recent appearance.
And you don't need multiple sets. You can just take them with you.
I don't
need a $2000 MacBook Pro. I use MacOS because I
prefer it to Windows, not because Windows running on cheap commodity PC hardware wouldn't get the job done. Frankly, unless my current kit dies suddenly, I don't need a new Mac at all - at the end of the day we're probably talking about a 50% speed increase over my 2011 MBP which is
nice but it doesn't turn time-for-coffee-break tasks into real time ones (the way 2-yearly computer upgrades did in the past).
Currently, the only adapter I need to carry with me is the miniDP-to-VGA adapter, which I only need to plug into data projectors on the hoof and can hence live in my travel bag (and if I do forget it, its easy to borrow one). I don't even take the power supply to and from work, because the cinema display on my office desk has that. My £500 price tag on docks & dongles wasn't what I could get by with - it was what would give me an experience
at least as good as what I already have.
Also put this in the context of a substantial hike in price c.f. the earlier generation plus - for many of us outside the US - an across-the-board "correction" for currency changes (which can't entirely be blamed on Apple but still has to be paid).
Sounds to me like you haven't actually sat down and added up your Total Cost of Ownership - "only $20" here, "only $20" there and "$50 for a TB2-TB3 adapter for a few months until the 5k came out" soon add up, and while the $2000 you've spent on new displays comes with the benefit of two very nice displays, you can't completely discount it.