$50k isn't really midmarket, that's more like upper SMB. Which definitely has more churn and less durable deals. $100-200k is more like midmarket. $250k+, but especially $1M+, is enterprise. The problem with $25-50k is that SMBs with single digit millions in sales can't really afford it. So they're going out on a limb, which means pressure for them and you. If the company is well into double or triple digit millions, it's less of a hole in the bucket, and probably less career risk for your point of contact.
I don't disagree with you esp. for a mature product/startup, BUT the article is discussing acquiring early-adopting customers. I don't know many early-adopting SMBs that would pay $50K with unproven market value.
Totally agree, thanks for writing. Mid-market is a mess for so many founders.