Why is this sh*t never as easy as you think?

So I wanted to swap a set of newer 35mm forks onto my CB450.
Here are some things I've learned over the past 3 weeks:

CB750f forks are 1.5" too long, but that can be worked around.
ebay forks were rusty but cheap ($40 for everything)
now I have to find a 2nd pair of legs
bellows won't work with DOHC dust seal
have less offset than K forks
stem too long
I bent stock CB450 stem pressing it out so now I need another
wider axle than drum front so I need to make spacers
no brake rod mount
fender prev. spraypainted so it reacts with lacquer primer.
broke new lower steering tapered roller bearing while test fitting so have to buy another set
no known stock-type fork ears work
CB750f upper triple has no stem pinch bolt, but CB450 stem has not enough thread for locknut
polished upper triple then dropped it.
then discovered pinch bolts are 7mm not 8mm like the ones I ordered in SS
no known dual-disk front wheel works with CB750f legs
legs are black so a PITA to sand/polish by hand

There's more but I can't remember it.

The lesson for next time?
- Don't bother with 35mm forks unless you're racing or unless it's a bolton swap like CB500t. It's just as much work as doing a bigger, modern setup.

- If you're going to do a swap like this just go straight for GL1000 forks with 39mm legs, dual disks, polished legs and a spoke front wheel. Then call Frank and have him make shorter tubes. Then call someone and have them build you a billet upper clamp. Then order a brand new fiberglass fender on ebay. Yeah, it'll be $500 by the end, but it will WORK.

This job has turned out to be a way bigger hassle than I expected, especially considering my own blunders.

There is so little interchangeability with this stuff, why is that?