People will prefer to use their vehicles rather than public transport, meaning that mileage will increase on older cars as owners will instead invest in keeping their vehicles on the road.
Due to global shutdowns, there will be a decline in the production and sales of new vehicles. Multiplying before mentioned with the global economic factor, new vehicle market demand will also significantly drop as a consequence, the average current vehicle fleet age will grow.
People and companies will face hardships so they should prefer reconditioned parts over expensive and overpriced OE/OEM parts.
We can even predict a scenario of shortages in the OE/OEM supply chains due to the shutting down of production facilities.
Last but not least, governments will start simplifying measures and regulations around existing emission standards bringing diesel cars back to former popularity levels.