Today It is possible, you can run almost any software in system unable to run them natively via cloud services.
I can run the last version of Blender (3d app) on my old computer with outdated version of openGl driver, the online run the app for me on their system, and I can use it freely but it is a little bit slower, more the a native installation.
Sony with their app "PS4 remote" we can play with the PS4 on a phone, a computer any hardware able to run app.
It will be cheaper (time consuming, components compatibility) for Sony to develop a console dedicated to run games via their cloud service, and for the companies it will cost $0 and 0 risk taking to develop a new (crappy) version of their games, because they already running on the big sister.
Business talking it can be a win-win, Sony can update their previous portable ps at almost no cost (the hardware exist already), and the game developing companies don't need to invest money in creating a "new" and weaker version of the game. Because today it is a question of time and money, companies try to save both today to make more money. If Sony find an (financially) interest to make a portable playstation they will do it, and they have at the date of today other priority like fixing some issues with the PS5 befor the launching...