Your post is really thought provoking for me.
But, first, why are you planning to go on ban? Is it something your truly want / need to do? I haven't tried to ban (before this last month) because I knew I was still refining my collection. It would have been frustrating to have a ban that got in the way of my curating goals. Now that I'm at the tail end of building and need to think about next steps a ban makes sense. I say all this because I want to encourage you to think about it and do whatever is good for you.
Now on to the second part of your post. You say you'll never have forever bags. For 90% of my collection is say YES! A thousand times YES! I like bags that are on trend. So I'm trying to buy more classics than not to avoid churn. But I know that other than
possibly my Chanel and Dior flaps, nothing will be satisfying for me in 10-15 years.
How I plan to solve it is I intend to buy on a rotation. Every year I'll add a couple bags and sell / donate a couple of bags. That will keep my collection fresh.
But, I hear you in that your situation is unique. You don't have a good resale market so you can't recoup funds as easily. Perhaps the idea is simply to set a yearly handbag budget. (Like people do with any hobby like cars, playing blackjack or skiing) Then you can decide in any given year if you want to spend it all on an expensive bag or split it amongst 5 less expensive bags.
My big functionality issue is capacity. I can deal with almost anything except no room for my stuff. Drives me crazy.
I used to be in your situation. My most expensive bags weren't getting used because they were "specialty" bags. When I realized this I got really frustrated; it felt like I had money tied up in museum pieces. So, I sold the specialty bags
and the less than exciting daily bags and flip flopped. When I know I need a super functional / high use bag (like the black tote), I've "forced" myself to spend well on it and get exactly what I want. And when I want something trendy or that will get less use, I strangle the budget for it (like the rose gold BV pillow I want. I won't use it much so if I buy it, I want to get it at a steal.) Over time this has meant I get lots of use from my most expensive bags and don't invest much in my specialty bags which makes me feel good about both sets of purchases.
I also decided I didn't want anything but premier even for my carefree bags. But I
refuse to spend 4 or even mid / high 3 figures on bag that should be able to be thrown around. My solution for that has been to hunt premier bags at crazy low prices (like my
Prada jute tote which is one of my beach totes). And I've been careful to get some of these with no / almost no branding since that is a necessity when volunteering, etc. (like my black Jimmy Choo hobo) This approach has given me the best of both worlds - a premier bag that makes me giggles happy at a price point that allows me to chuck it around if need be.
And, to your last point. It absolutely isn't crazy to only want premier. LOL! You want what you want and (budget allowing) shouldn't buy anything but.
Some people only buy contemporary brands like Massaccesi and
Coach. They are choosing to spend more to get those brand's bags vs. functional and cute bags available for 1/10th to 1/2 the price. Are they crazy for only / primarily buying contemporary handbags and refusing to buy $30 real leather bag with sub contemporary or no branding? Nope.
Are people crazy to only buy new and not "save money" on preloved or vice versa?
Are people crazy to eschew variety and have a capsule collection of 3-5 bags? Are others crazy to have 250 bags and not use half?
I guess the point I'm trying to make is,
get the bags that make you happy. My only suggestion is to make your everyday functional bags your most expensive ones so you feel good about the spend. And, you can always have a couple of back up non branded premier, contemporary or sub contemporary bags for alternative situations.