It used to be that orders that used PayPal and Etsy payments caused an issue but no longer maybe unless it was a stand alone PayPal. However I don't think Etsy's PayPal would allow this deal. Etsy has Klaarna for that.
It's also possible the items in the cart especially if they sat there for a bit had a listing change which usually means Etsy wants you to review.
Other possibilities are credit card limits. Even if you think have enough credit, you might not have. Sometimes credit cards limit what can be bought from certain parts of the country or world. Some CC cards impose a limit for a certain amount in single transaction.
The payment processors are the ones in charge of the finances and they follow guidelines established. Etsy has to follow what they have to follow.
I've been on other sites where I had to split or process differently. It's not just Etsy. And some sites when you reach a certain price point get really picky.
As a buyer on Etsy I have no issue with their current guidelines. If I want to make a huge purchase I would check with my bank first to make sure the payment can go through. After all banks and CC companies hold the strings. In fine print can be some interesting information about how, when and where purchases can be made.
And this is first time I know of that this has been brought to attention here in the forums so either it doesn't happen, doesn't happen often enough or the buyer just buys what they can. If this was truly happening a lot there would be sellers who are also buyers here complaining,
