I am also have the question about OP questions. So i search some possible factors why segwit is not that popular to most of us. Will highlight the important matter.
The problem is that those arguments are incorrect. While they are what people believe, they are also false.
1. SegWit doesnt solve the most urgent capacity issue - SegWit, which is a soft fork solution for malleability, cannot solve the capacity problem.
It does not solve the capacity problem (there really cannot be a solution to that problem though), but it certainly helps. The redefinition to block weight and the lower weight given to segwit spends helps to increase the number of transactions in a block.
Furthermore, by fixing transaction malleability, Segwit enables 2nd layer solutions like the Lightning Network to work much better and more securely. These solutions allow for even more transaction capacity.
2. SegWit will deepen Cores impact on the community - As an implementation reference for Bitcoin, Bitcoin Core was of significant influence in the community. However, their influence has long been overrated by their actions. By abusing their previous influence, theyve obstructed Bitcoin block size increase from happening, against the will of the community.
The problem with that is that the Bitcoin Core developers did allow a block size increase to happen. Segwit is a block size increase, and it happened. Furthermore, if Bitcoin were ruled by Bitcoin Core, then Segwit would have activated immediately after it's release, not 10 months later.
3. SegWit makes it harder for future block scaling - On technical terms, SegWit uses a transaction format that can be spent by those who dont upgrade their nodes, with segregation of transaction data and signature data. This means SegWit is irrevocable once its activated, or all unspent transactions in SegWit formats will face the risk of being stolen.
That is the nature of ALL soft forks, not just segwit. All soft forks are irrevocable once activated, or all unspent transactions that used anything deployed in a soft fork can be stolen. But also any fork that "reverts" segwit (or a different soft fork like P2SH), will just be a hard fork.