A lot is riding on whether or not digital behavioral health operators will be able to solve the challenge of high customer acquisition costs. Last year, investors poured $5.5 billion of capital into digital operators’ coffers.  Yet high customer acquisition costs remain a largely unresolved concern that could limit digital behavioral health’s promise of speeding up access to care and alleviating local provider shortages.   Many of the big players in the space, including Teladoc Health Inc. (NYSE: TDOC) and Talkspace Inc. (Nasdaq: TALK), face a heavy cost burden in advertising costs associated with customer acquisition, driven by the rapid expansion of digital health companies generally following years of elevated investment.…