Will Streamers in use today remain compatible within a Digital System in 20-40 years time.
A Seller will most likely suggest they will, a IT savvy individual may say something that is close to the opposite.
Hard Media Live on as long as the embedded data remains readable and a signal is produced.
Hard Media and Hard Media Players are a tremendous Bang for Bucks, when longevity is included in the equation. My Youngest TT and the last one bought as a New Item in my collection is 30 Years Old. My Oldest Vinyl LP Album purchased by myself and still in use today is 40+ Years Old. From my understanding, I do not have a Item to support the Analogue Source that in today's market is worth less than the purchase value. The Analogue Source does demand a reasonable proportion of Real Estate to support the care of it.
The CD Source depending on size of CD Collection does demand similar Real Estate when the collection is vast in numbers.
An individual who I met on a few occasions migrated from their 25000 CD Collection to take up streaming. They stored the CD's in the homes loft space and the weight damaged the timber roof trusses.
Stored CD Data as a ripped file is no where near the 2.5 Tonne CD Collection will weigh in at.
Stored Data is not my forte, I am not able to be producing a system to be failsafe, some with much more savvy than myself will have methods but exactly how failsafe are they, in comparison to having the hard media at hand to be used when desired. Data can disappear, and not like the best magic trick be brought back for all to see shortly after, for some without all the correct measures in place, when Data is gone, its gone Data.
The next question is for those with a safe Data store, how long is it in the near future, before new technologies does not recognise todays stored Data as a readable Data?.
I sense but can't say with full conviction, that the devices in use as a Source that are a Streaming System, are to become the most short lived out of all the Audio Sources produced in the past 70 Years. I fail to see how a device used for Streaming in use today, will be a Item that circulates in the Circular Economy and is wanted to be used in 2050, but do see both Vinyl and CD that are healthily being circulated in today's Circular Economy, maintaining its place in this marketplace and be seen used regularly and not be an underground Source in a System in the future.
I am always intrigued when Hollywood releases a Film giving an insight into the World in which my descendants are referring to me as a 10 x removed Grandfather or even more. There is in many films a Turntable in use.
What is not understood is the need to still use the Cartridge? Or even the TT?Surely a Micro Drone with a Data reading device would be able to track the Groove and Beam the Extracted Modulation Data as a Facsimile of the embedded Data to the microscopic processors used to interpret such Data, which would most likely be processors traced into the Film Material selected to produce air movement and an End Sound 
.
I've always considered my interest in Vinyl using present technology as myself being one who has given Vinyl a future.
I'm going to miss the future of Vinyl, where there is not need for a Mechanical Interface. Vinyl being dropped into a Linn Chamber and propped on a Rotating Invisible Force controlled to a rotational speed where nano seconds are the fluctuation of Speed and the Koetsu Micro Drome extracts the Data for beaming Down Stream. " What a bummer 
", I've worked my life towards this as the design to replay my Vinyl Collection.
I'll have to content myself with the Hope one of my owned Albums survives through to the future period to meet such a replay system.