This is why it's wise to do it only temporarily, in case BIP110 does break something.
It won't be temporary. Even now, before BIP-110 activated, you want to use stricter rules, by activating next BIPs:
https://bitcointalk.org/index.php?topic=5582070Just imagine if we had done Taproot as a temporary upgrade.
Do you understand, what would happen, if Taproot would expire? Then, all P2TR coins would be spendable by anyone, without any signatures, unconditionally. Which means, that all users, who used P2TR, would lose their coins in that way or another. Because what can be done with a coin, which is spendable by anyone? You can let it to be stolen, or burn it, by throwing it out of circulation. In both cases, real users lose their funds.
Taproot's "speedy trial" was completely useless.
Then, why
Luke wanted to mandatory activate Taproot, even if it wouldn't be supported by miners? Why he wanted to do that in the same way, as he is doing it for BIP-110 now? Why he created a separate client, which forced Taproot activation, while in Core, it could simply fail, if not enough miners would signal?
If you are disappointed, because of Taproot, then go ask him, why he forced it in his client. If Taproot would fail, then Luke's client would fork into a minority chain back then. Speedy trial actually pushed both clients to the same chain.
I think, in the future, all upgrades should be temporary.
If they would be, then it would be risky to use any new features. Which means, that all users would just stick with P2PK, because it is the only address type, which is present since 2009, and is used absolutely everywhere.
So, do you think, that everyone should stick with uncompressed P2PKs? Because even compressed ones is a feature, which was discovered later. Satoshi used only P2PK uncompressed keys, which is why he hashed them, to make addresses shorter.