The big problem with that is that it would have made the ACA even less popular.
I remember Reagan putting in place a plan to help the elderly with nursing home care that they had to repeal because it was paid for by the elderly themselves who were up in arms about being held responsible for their own benefit.  The lesson is that asking something of the taxpayer is one of the biggest mistakes a politician can make.
The people who designed the ACA expected more people to do what this employer did with paying the penalty and push more consumers onto the marketplaces and increasing the number of healthy people in the risk pools.  They expected that over time health insurance would become an individual thing instead of employer based.  That would have helped the economy as a whole and US competitiveness on the world market where other countries charge for health coverage through taxes.