There are some that have emulated it, but the team that was there and created Heroku cared deeply about developer experience. When you just "clone" that you miss pieces, one PM friend that I worked with at Heroku called them papercuts. We would obsess over such things and the quality of something being shipped.
Even now if you emulate that it's one thing, but Heroku has been frozen in time for at least the last 5 years, maybe closer to 7-8 years. There was more to do and more to improve and advance, and it stalled out for reasons. Now just being a clone wouldn't be enough you need to continue advancing the experience.