I used to think that as well, at first.
Let's be pessimistic and assume everything SSedan listed (plus the MCU) is going to fail, even if it doesn't.
0. Keep my P85: $0
1. Replace primary charger: ($2200)
2. Replace TPMS computer: ($600)
3. Replace brake rotors and pads: ($700)
4. Front suspension repairs: ($1260)
5. Pack heater replacement: ($400)
6. 12V replacement: ($220)
7. Washer pump, no labor: ($40)
8. Replace charge port: ($400)
9. Replace 4 door handles: ($1600)
10. Replace MCU: ($3500)
Total spent:
$10,920
Now compare the alternative:
0. Sell my P85: +$40,000
1. Buy equivalent Model S (100D): $119,000
Total spent:
$79,000
The equation changes slightly once the 8 year drive train warranty is up, but it's still cheaper to replace the main battery pack and DU than to replace the car. Also, there are several things I continue to appreciate about my P85 which Tesla no longer offers:
1. Rear-wheel drive performance option. (This is a personal preference; most owners would likely choose all-wheel drive.)
2. Larger frunk storage space, partly due to #1.
3. Pano roof that opens.
Just some thoughts after 5+ years of ownership. I may reconsider later after I get to drive a Model Y or a Cybertruck.