Lots of hardware is used for multiple decades, but has software that is built once and doesn't get continuous updates.
That isn't necessarily laziness, it's a mindset thing. Traditional hardware companies are used to a mindset where they design something once, make and sell it for a decade, and the customer will replace it after 20 years of use. They have customer support for those 30 years, but software is treated as part of that design process.
That makes a modern OS that can support the APIs of 30 year old software (so 40 year old APIs) valuable to businesses. If you only want to support 3 versions that's valid, but you will lose those customers to a competitor who has better backwards compatibility
That isn't necessarily laziness, it's a mindset thing. Traditional hardware companies are used to a mindset where they design something once, make and sell it for a decade, and the customer will replace it after 20 years of use. They have customer support for those 30 years, but software is treated as part of that design process.
That makes a modern OS that can support the APIs of 30 year old software (so 40 year old APIs) valuable to businesses. If you only want to support 3 versions that's valid, but you will lose those customers to a competitor who has better backwards compatibility