1/ How do you measure what's a 'good' blockchain platform? Dev adoption and the quality of it.

Everything else such as plans, resumes, claims, testnets, mainnet launches, are meaningless and are just words.

Put your trust in where quality teams are choosing to build.

2/ Until you see that happening, believe nothing.

The failure rate on platforms is huge. Of hundreds over the last ~5 years+, that countless fans/communities claimed would be huge (taking words and promises as fact), we have around 4-5 that have ended showing signs of adoption

3/ Making a successfully adopted platform is magnitudes greater in difficulty than a normal project and requires vast resources.

You cannot know beforehand which will 'make it' and start to get significant quality adoption.

4/ This is why anyone who tells you that X platform, ( that only just launched its testnet/mainnet and is yet to have any significant adoption) has a great future, is either clueless about platforms OR lying in order to shill you