My major work travel period was in the period roughly 12-18 years ago. The programs we knew back then (I was AA EXP throughout that time) were completely different from the programs we have today.

• As you've noticed, elite status earning is revenue based nowadays
• Airlines have learned how to better monetize their premium cabins, including via (paid) upgrade offers in app. The number of seats going to complementary upgrades is lower nowadays than it was back then. Across the US-based airline forums at FT you will hear the mantra WFBF (want first, buy first). That's the new reality (that's not to say that upgrades never happen, but don't count on them)
• The value of miles for redemption has been devalued, devalued, and devalued some more. And will be devalued again.
• (none of the above is specific to UA, you'll see it at DL and AA too)

This doesn't mean that you can't find value in status, especially if an employer is helping to pay a lot of the travel cost. But you definitely want to carefully analyze the benefits you might (and might not) get before you pour any of your own money into status versus just using that money to buy the product (E+, F, etc) that you want.