Assuming that Bithority succeeded in solving the financing problems of miners when the market is down and the return is low, but it did not solve the problem of “mining centralization”, as there are costs of establishing a mining farm that only investment funds can bear, in other words, you solved a problem that miners do not complain about while Bithority's idea is to decentralize mining, something it has not achieved.
vastly help to decentralize the Bitcoin mining ecosystem
OK but...Forget miners...There is also costs of buying Bitcoins for Bitcoiners, right?!...Should other poeple supply their costs for buying Bitcoin?..No! This is the cost that anyone should supply himself regarding his pocket size! Otherwise Bitcoin would get worthless! Therefore, there is a cost for any value! and I think that's clear enough....So, lets rephrase your question more reasonably: How can we decentralize the cost of establishing mining farms (capital cost, not operating cost!) for "wider range" of investors? (bcuz not everyone can and should start mining...there are some requirements!)
answer: Bithority will be able to provide the necessary infrastructure for even capital cost financing later on, when it can catches enough traction from folks in Bitcoin community. For instance, miners who already have running mining farms for a while, they can get a credit score from the Bithority token holders so that they apply for financing their Capex of mining. And definitely, as in many financial means, there will be some risk for those lending money for the capital cost (establishment cost) which Lenders should accept and deal with. So you see this is already been implemented in many lending platforms and even without Bithority!