As what comes to fundamentals, they lack developers and adoption. ~What XML lacks a lot is community hyping it. I have not seen it mentioned in anywhere.
there was no real development during recent years and at the same time the competing currencies developed dramatically So big that it became impossible to catch up with them.
Quite the contrary, I see the opposite. I don't know XLM's history but recently there are some development within the XLM ecosystem. I remember there was some DEX development but halted due to how the system works a year ago. Right now, they are focusing development of their new smart contract layer/platform, Soroban.
The system limitation of what seems to be holding back XLM seems to be resolved by Soroban. Nevertheless, it is still in the developmental process, so it is not yet ready for production or the masses. One thing they focus on besides Soroban developments is developer relations. There are various grants and promotions that specifically attract programmers and builders to build things on top of Soroban.
The way I take it is currently they are focusing to build things first, then after the ecosystem is established, an adoption campaign will come.
https://stellar.org/blog/a-developers-guide-to-soroban-adoption-fund-programshttps://stellar.org/blog/stellar-quest-live-series-6-fast-cheap-out-of-controlhttps://soroban.stellar.org/