if you can't fix the testnet and just reset it with new conditions then, what are you going to do on the main chain?
This is a very good question, and I also posted it on the mailing list:
so mining is not doing a great job at distributing testnet coins any more
It is a feature, not a bug. Would people want to reset Bitcoin main network in the future, for exactly the same reasons? Or would they want to introduce "tail supply", or other similar inventions, to provide sufficient incentive for miners? This testnet3 is unique, because it has quite low block reward. And that particular feature should be preserved, even if the network would be resetted (for example, it could be "after 12 halvings, but where all previous coins were burned"). And not, it is not the same as starting from 50 tBTC, as long as fee rates are left unchanged (and 0.014 TBTC means "the ability to push around 1.4 MB of data, with feerate of 1 sat/vB", instead of 50 tBTC, which means "pushing 5 GB with the same feerate").
Honestly, I don't understand yet why tBTC has value to some people?
1. Because it is the only decentralized test network, which works continuously for more than a decade.
2. Because it has almost all rules, identical to the main network, so it doesn't contain a lot of mistakes and quirks, made by many altcoins.
3. Because the whole chainwork is enormously huge, if you compare it to other test networks, like signet or regtest.
4. Because it had a lot of halvings, so if you compare amounts, which you can get for free, then they are closer and closer to something, which you can get from real Bitcoin faucets.
If this is a testnet and this Bitcoin is not real and has no real value then why are some people interested in buying it?
Because it is great for data pushing, without being censored. If you use Ordinals on the main network, then someone may argue, that you stop the real payments from being processed. But in testnet, coins are supposed to be worthless, so publishing your test cases is the only thing you are supposed to do.
Also note that testnet allowed non-standard transactions by default in a lot of old versions of Bitcoin Core (it was changed in some recent releases, like 26.0). Which means, that there are a lot of miners, actively including non-standard transactions into blocks, and many people rely on that assumption. And that allows pushing data in more efficient ways than on mainnet, and also performing more tricks than usual, for example by not using any address type, and relying on raw Scripts (because then, you don't need any workaround for informing other users about the script behind your challenge in a decentralized way).
Or are there other uses?
There are many use cases for a test network. Even if you would have a chain with zero supply, where all coins would not pass any value, then still, there are a lot of consensus rules, which are active. For example: the whole Script is followed to the letter, even if you send zero satoshis. All locktimes, difficulty adjustments, and many other rules are preserved. And the whole protection from chain reorganization is still active, even if you have some chain with no coins.
Note that in testnet3, there is one main reason, why you have coins with any amounts: to be protected from spam. To not flood the network with a lot of transactions, created out of thin air. This is the reason for transaction fees, and this is the reason for coin amounts in the first place. Because if not that, then if test coins are supposed to be worthless, then ask yourself a question: why any coin amounts are introduced at all, and the total supply is not just permanently set to zero?
And of course, there are lots of use cases for coins with zero satoshis. For example: any token creation protocol could potentially use the UTXO set to store that kind of information. And in that case, testnet fits even better than mainnet, because you still cover things with a lot of hashrate, but you don't have to take down regular payments, because this is not the purpose of the network, so no real payments are expected in the first place!