>> The roof part of Tesla solar roof should presumably last a long time.

Ya, but people aren't buying a tesla roof for the roof part. It is the solar part that matters. Roofs move, they swell and shift with the seasons. Over 25 years at least some of those thousands of connectors between solar tiles will have degraded and/or disconnected, leaving entire sections/rows of tiles disconnected. That is why, when you need to make thousands of connections in an electrical project meant to last many years, manual soldering is still the preferred tactic.