I have 20,000 miles on my Pirelli Scorpions. I drive less than 10000 a year and they are soft miles. Dealer is trying to sell me a new set. Beware the upsell Roverites. Beware.....

 

You should be able to visually check for yourself - Tread depth flush with ware bars.
You should be able to technically check for yourself - Tire tread depth gauge. Tire vendor will have min tread specs.

OEM tires (My experience) are usually @ 30-35k miles until ready for replacement.
Tire rotation is key. If you have two warn out front tires all four will need to be replaced or two new cut/shaved down to exiting tread depth.

My JLR dealer matches tire rack and Costco prices.
Yes car dealers are in the business to make money.