The current Quicken Mac programming team is larger than it was a decade ago, but it's still fairly small. And that's what's been happening in the nearly eight years since then. But the product manager for Quicken Mac said at the time that they decided to release what they had, and add to it and improve it incrementally over time. The first release of the modern Quicken Mac came in late summer 2014. It was poorly received by users, and before they could improve on it, there was a major management shakeup, and development ground to a halt. After the multiple mistakes, dead ends, stops and re-starts, and lost years, in 2013 they set out again to build a complete Quicken Mac, but they hired only a handful of people to work on programming it. The first attempt was so bad it never made it out of beta testing the second attempt was the 2010 Quicken Essentials - "essentials" because it was a very limited subset of Quicken functionality. Quicken at that time was owned by Intuit, and the brain trust there decided to create a new uniquely Mac personal finance program rather than just trying to create a modernized version of Quicken 2007.
When the fundamental changes from the original Mac operating systems to the Unix-based Mac OS X required them to start over from scratch, even with the blueprint of what they had done before, it was going to take a long time to program all the features and functionality using new tools, programming languages, frameworks, etc. You're right, and the trail between then and now would be comical if it weren't so painful! The first thing to realize is that Quicken 2007 was the culmination of about two decades of programming work. One final comment/question: why is it so hard for them to make functions from 2007 available in the newer versions? That was 15 years ago!
(Can you upgrade your Mac one step, from Sierra to High Sierra? If so, current Quicken Mac will still run on that OS, so you can buy it, try it for 30 days, and get a refund if you decide it doesn't work for you.) But if you're not downloading transactions, and doing basic bookkeeping, the odds are good that you will find it good enough. I can tell you that I've found Quicken Mac meets my needs - but only you will be able to tell if Quicken Mac meets your needs. Some missing functionality will come in the future whether 100% of every Quicken 2007 feature will get implemented is less certain, as there are some things the developers may decide were used by very few people. There are some partial equivalents to Quick Reports, but you can't do everything from Quick Reports. You can't generate a report based on the text in a memo field (but you can do a Search on memo text, and print the results as a report.) You can generate reports for most investment data, but you can't yet save them as named reports, so you may have to play with the settings in your portfolio each time you want a particular investment report. For instance, you can't specify multiple levels of sorts/subtotals by rows.
For a few people Quicken Mac still doesn't cut it. But for most people, the reports are fine, or at least good enough. Do they have every feature of Quicken 2007 yet? No. Reports have improved a great deal from Quicken 2007 to modern Quicken Mac. But after I worked with Quicken Mac awhile, I found I like - and preferred - the one-line display, and found returning to look at things occasionally in Quicken 2007 actually jarring. The first time almost everyone switches from Quicken 2007 to modern Quicken Mac, they say "where's the 2-line register display?!" I did.
(I was still using Quicken 2007 back in 2017, because Quicken 2017 was missing too much for me I eventually switched to modern Quicken Mac in 2020 because there had been significant improvements in reports and other areas of the program.) Since you have a copy of Quicken 2017, you may be aware that you now get constant notices when you launch it to upgrade because of changes and security upgrades, even though you aren't downloading transactions. It lacks a lot of features and fixes which have been made over the past 5 years. Quicken 2017 was the last non-subscription version.
They also need to keep adding features which users demand, many of which existed in Quicken 2007 or Quicken Windows and haven't yet been built for the modern Quicken Mac. Even if you don't use online services, they need to keep maintaining the program to work with the annual changes in the Mac operating system. (Note that it's not an "online subscription" Quicken is still desktop based, just as it has been.) This is the business model which keeps Quicken afloat. No, there is no alternative to an annual subscription.