Where our story digresses is that we got paid traction quickly. Early on we decided we wouldn't be free and we'd convince schools(& parents) that we offered enough value to pay for it. We narrowed in on a very specific need, focussed obsessively on quality, provided our teachers fantastic customer service, kept our burn rate very low, bootstrapped(it was hard) and just buckled down and executed.
Along the way, somehow, and this was crucial, our teachers turned into evangelists - parents, principals and administrators took note. It wasn't that they just liked what we offered -- they went to bat for it. Many of our teachers spent 8+ months convincing their principals and district officials to buy us. Private schools were crucial in the beginning to get our cash flow going, public schools took longer but we waited patiently (and nervously)
The current ecosystem is not friendly to Ed startups, it's stacked in favor of the large Ed vendors who have the manpower to closely follow budget allocations, develop long term relationships across 50 states and have deep knowledge on how to work the system.
OP, congrats for sticking to this for so long. I suspect that it was incredibly draining but along the way you've helped countless teachers & students and that should count for a lot.