I think it is something that happens naturally.
It happened in the past, DApps are born under the shadow of some blockchain, they grow, increase the number of their users, they develop and, at some point, they consider what to do to continue growing.
I remember DTUBE DApp, the decentralized YOUTUBE created on top of the STEEM Blockchain, with a lot of support from the former owners of the so-called blockchain, STEEMIT Inc. I remember that this service had a resounding success but, over time, the relationship between DTUBE and the STEEM's biggest stakeholders was gradually degrading. So much so that at one point, DTUBE developers decided to bet on creating their own blockchain and projecting their own economic and governance system.
Another example is APPICS, a kind of Instagram Like app with a lot of support and great Marketing work, built on top of the STEEM blockchain and maybe one of the first which creates its own token, also at Steem-Engine 2nd layer. Again, in order to further develop and possibly also for better control of its economical plan, APPICS is planning its transfer to another blockchain, TELOS a fork of EOS. In this case, they are not creating a new blockchain but prefer to work on what they think is a more scalable, faster and secure blockchain than the one offered by STEEM or HIVE, according to them.
Outside of HIVE / STEEM this situation happens continuously, possibly growing on ETHEREUM blockchain as a Token and then deploying their own blockchain and economic model. EOS or TRX themselves were incubated inside ETH Contracts if I am not wrong. With the time, they manage to develop their own blockchain.
As far as I know, anyone can clone the STEEM protocol, setup their variables according to their economical plan and create their own blockchain with their own governance DPoS algorithm. It was the case for HIVE, which, fortunately after the last HF has become more independent of the old protocol, but also for other cloned blockchains as SCORUM or more recently BLURT.
BLURT is not so different from HIVE or STEEM, actually it looks like another Community with the difference that they are totally free of the Second Layer dependence on which communities are linked with.
They also have changed their economical proposal, curation split, fees and witness system to the point that it is becoming an excellent example about how can you do things differently. Additionally, their main website frontend (https://blurt.blog/) and wallet works very efficient and they have managed to get listed already in a few minor exchanges.
The Case for LEO's independence from the HIVE blockchain
LEO is possibly the most successful HIVE community to date. LEO vision has grown exponentially, and continues to do so. Not only developing and obtaining excellent tools and interfaces but also employing all possible strategies to drive the TOKEN price to a sustainable growth level. Among other measures adopted by its developers, the implementation of a recurring burn of tokens, the acceptance of advertising in its interfaces that generate a revenue with which to "buy" tokens and burn them generating scarcity and value and the implementation of a system of 50/50 curation without rewarding window and curation curve have proven to be excellent measures for the growth of the project and the community that supports it.
Although the relationship between the HIVE blockchain and LEO is excellent, LEO has decided not to depend exclusively on HIVE but to introduce the ETH ecosystem also in its DNA with which it is possible to create an account in the LEO community without necessarily having an account in HIVE.
This is an incredible advance and it may also generate new users in HIVE but not necessarily.
LEO follows its ROADMAP with surgical precision, which, on the other hand, does not aspire to see the future in the long term but does so in the short-medium term with which its development is unstoppable.
LEO is becoming an independent entity, its degree of autonomy from HIVE is almost absolute and only its dependence on Hive-engine keeps it somehow "tied" to said blockchain in my opinion.
There is no doubt that the secret of its success is its incredible internal ACT PLAN DO CHECK process, supported by an excellent team.
Lately, H-E and HIVE are debating about the possible future decentralization of Hive-Engine, which would also affect the communities and tokens created within... That could be indeed an advancement towards the right direction in this blockchain ecosystem but I wonder if, at this level of development and excellence in which LEO has been able to reach, wouldn't it be better for LEO to work on the development of its own blockchain, or cloning an existing one, adding total decentralization and governance to a product whose projection is so promising.
If this happen, LEO would become a full-ended product, understanding that only upgrades and implementation of economical measure would be always needed.