Should I do IRA to Roth Conversion at age 69 years old?

I would  like to know if it was prudent for myself and spouse {MFJ} to Convert {~600K}  IRA funds into a Roth in annual {smaller} increments of 20-30K annually over <20 year, in spike of fact I’m in the 22% Tax bracket due to annual SSI & Pension funds.  

 

Rationale:  Based on fact that money gets taxed at the highest rates, the marginal rates, and so your tax rates will be increasing over time and with the RMD tax rate which increases each year.  The tax rates are also set to revert back to higher rates in 2026. If I or spouse pass away the other will be a single filer with again higher tax rates. Not to mention Medicare surcharges, National debt forcing higher taxes, etc, etc. Also you will leave beneficiaries with taxable income and therefore less money is passed down to them.

 

I was informed in younger years that Roth Conversions are popular when your in your 50’s, so at retirement age it’s not effective, due to present value of the dollar, and not enough time to generate the Roth income.

Any ideas on this? I notice there are some Financial Companies pushing this concept as well?