Not exactly though. There is always discounted cashflows as...

Not exactly though. There is always discounted cashflows as ultimately were trading shares in a company. Basically, TLG has the potential to eventually become profitable - something i would like to think we're all hoping will come to fruition. At which point shareholders will own an income bearing asset. You can probably guess at how much income per share the company will earn, then work out how much of that will be profit. Work in some expansion estimates and then determine your growth expectation.
How much are these shares worth to you? How much can you pay for them?
If you find value despite the risks then maybe you could consider changing your sentiment.
Of course, there are many ways to determine worth. Maybe you use another approach, thats cool too. Many here would have loved to track moving averages to determine optimal times to move in and out, but that isnt the only skill set you can apply to these type of assets.
Only time will tell if TLG has been a worthy hold. Either it will be a success or it won't - but the share price and the operators will have little to do with that.