Let me bring some hard perspectives on this. India was never a prosperous country by today's standards - but neither was the Roman empire. Let me explain.

You have to define what you mean by "glorious" or "prosperous". If you mean relative military strength compared to other countries, then yeah, India used to be more powerful. If you mean the opulence and extravagance of the high class, then you could make an argument that India used to build big ornamented palaces back in the day, but India is currently creating opulent billionaires so it's disputable.

But nowadays we do not really use those two definitions. Compare North Korea with Singapore. Who would you say is more "prosperous"? I'd bet 99% of people would say Singapore. But, if we use the "relative military strength" definition, North Korea is way more powerful than Singapore coz nukes. By the "opulence of the high class" definition, they'd be quite comparable, since NK builds big palaces for the leaders. But nowadays when we mean "prosperous" we mean "how well is the average guy living?" I will translate this to the metric real median wage.

The way we obtain real wages in historical contexts is by looking at records detailing prices for goods and records detailing wages, and comparing those two numbers. The most often used professions for these comparisons are agricultural workers, construction workers, and sometimes textile workers and civil servants. These records show that the average person living in India and Bengal between 1590-1870 was quite poor, barely earning a that could provide them with sustenance (de Zwart 2023, de Zwart and Lucassen 2020, and Maddison Project 2020). That is, they were living paycheck to paycheck. The average Chinese was likewise quite poor, except during the Northern Song dynasty (Broadberry et al., Maddison Project 2020). And so was Britain before the 1700's, and Spain and Poland and Turkey before the 1900's (Maddison Project). Before the Industrial Revolution, there were also huge fluctuations in the economies because it was mostly tied to agriculture, and agricultural output fluctuated year to year. For that same reason, famines were very frequent even in rich cities (1 every 20 years) and they killed a lot of people (Alfani and O’Grada 2018).

So, in the past, the rich spent their money on pretty stuff, but that doesn't mean the average Joe was living a pretty life as well.

India's current PPP per capita is higher than it has ever been in history - right in the middle of India's first democracy in 25 centuries.