

You would actually need server racks at major ISPs colocated near customers (like netflix does now) to have acceptable latency. To have acceptable performance you would need a cheap small form factor PC, a monitor, a keyboard, a mouse.
None of this is free and if not fucked up on the software side would perform fine as far as normal computing tasks by itself.

A tablet screen is too small to use with apps not designed for such a screen. So it will be 100% useless without an actual monitor. Your TV is shit its got shitty text rendering, its massive, and if its 1080p 50" its DPI is shit if its 4K is barely acceptable you are too far from it to be usefully used and you have nowhere to put an actual keyboard.
During operation it will be decoding video 100% of the time so its battery life will be trash on a typical tablet battery and it will get hot.
You could solve all those problems by putting the hardware in a shell with or without fans a bigger battery a keyboard and a screen. Oh look we just re-invented the laptop! Except it only works at all in areas where you have wifi and it costs $30-$50 $50-80 if you have no upfront cost and have to pay for the hardware a month and either you have to manage updates and potential failures on both client and server OR only on the client but the server OS is so constrained that you have no control over it. It is worse and more expensive.
Do please explain what exactly one does with just a slow tablet? Do you use your finger to scroll the too big interface constantly on a laggy interface on your bad wifi whilst your virtual computer slows to a crawl when too many people are home OR do you squint at the poorly sized blurry interface 8 feet away on your 50" 1080p?
People already understand and buy laptops. Why will they buy this?