May be in olden days this statement would have been true, "Process Improvements do not result in specification change". In todays modern world, where we see new innovation left and right on every corner, not one but there are several such example where specification limits were changed.
Examples
1. Earlier if customer needed a spherically hollow part with say 3mm thickness, they shared drawings with 2 'C' type parts which get welded and then become sphere. Now with innovation in metal 3D Printing, with little changes full Spherical parts will be 3D Printed. Now Specification Limit (drawing) changed completely, as a single solid part. In My Previous Organization we printed such a part for a defense customer.
2. Earlier if you need a Burger after ordering we used to get in like 15-20 Minutes. Now with Innovation by KFC & Mc Donald's they deliver within 5 min. Now Customer specification (expectation) changed, We need Burger with in 5 Min of order.
3. Earlier for booking a cab we need to inform well in advance in 2 days or 1 week that we need a car on so and so date. Now after innovation by Uber and Ola, The movement you decided you need a car, you can get it in 5-10 minutes of wait. Decided to change the destination no worries go ahead, Customer specification limit (expectation) changed now.
4. Earlier when you order grocery online / Food Items in initial days they used to take like 4-5 Hours. Now with innovation in delivery apps, In 30 Minutes you will get your food items and grocery (Zomato, Swiggy).
5. When Dominos said "Delivery in 30 minutes or free" then specification limit for delivery time changed.
6. Earlier if you buy any items online or in showroom there was no refund option. Now after innovation by Amazon and Flipcart in supply chain they guarantee 30days refund guarantee Customer specification limit (expectation) changed. Now almost for all the products you have return policy if you do not like it.
7. Earlier for Mobiles there was not even 2GB storage capacity. After innovation by Iphone, Samsung, Nokia and now Customer specification limit (expectation) changed its 128, 256, 512GB. For Ram as well Customer specification limit (expectation) changed 16GB ram for Mobile is no longer fancy its a new specification for some customers.
8. Mobile internet speed, Earlier for Mobiles specification was 2G then it changed to 3G later 4G and currently 5G.
9. Earlier Laptop users were looking for 256GB hard disk and now Customer specification limit (expectation) changed 1TB and 2TB is like minimum need now, same also goes for Ram of laptop.
10. Sports cars when they initially stated speed was as far as what I remember it was somewhere around 150 KM/Hour. Now Customer specification limit (expectation) changed 304.7 MP is the new fastest speed for sports car.
Summary
All the innovations that happened in one company have become a norm in that particular sector / Industry. So ya customer specification has been changed and same were expected from other competitor suppliers, as on when a new innovation happened.