If TT2019 will not install on WIN7 and there is no compatibility mode option, then we are stuck.
We do not know that for certain yet - this is a big "IF". It could very well be that the 2019 versions will install on W7 machines. You just cannot reasonably expect Intuit to provide support for an OS that is no longer supported by its developer.
As an aside, there are only, to the best of my knowledge, two (2) other companies that develop consumer-level income tax preparation software for installation on customers' computers. It will be interesting to see whether they support Windows 7 (I am betting they will not support it either).
Footnote: everyone should be aware that there are some liability issues here in supporting an outdated OS, particularly when customers are generating documents/files with such sensitive information as taxpayer identification numbers, et al.