They canceled it because of poor adoption rather than any technical issues.
Which if anything looks worse for Tesla long term. If luxury car owners aren’t willing to pay 200$/month for self driving then trying to up charge people buying used model 3 and Y’s after canceling the S and X looks dubious. Which means that 100$/month subscription likely loses them money vs an 8k purchase.
Mercedes system was pretty useless because you could only use it in very limited conditions (specific freeways, only following another car). Nobody wants to pay $200/month to use it for 5% of their driving. Tesla FSD drives for you end-to-end.