What is this insulation thing you dwell upon? You seem to equate electrical insulation to thermal insulation. Nothing could be further from the truth. And for electrolytics it's only an issue when they dissipate significant power. Which is rarely.

Those 85c warnings are so near the boiling point that it's not just "warming". When you get capacitors really hot they fail. We knew that, before you mentioned it.

What's your point?