India is growing quickly but there are still many major hurdles it has to overcome before its economy will truly take off. It needs to invest much much much more in basic infrastructure, including roads and schools. It lacks a robust education system. Another major thing is the ineffecacy of its central government and also the lack of an unified taxation system.
Even if they fixed all that and the economy took off, there's still the second part of the catch-up effect, which anyone took Economy 101 will know, that is the last part of the catch up is very very hard. Even to this day, Japan hasn't caught up to US's per capita wealth and US hasn't caught up to Western Europe's standard of living. It's easy to catch up in early phases, like US in late 19th century, Japan in 80s and China in 90s, but eventually you hit a wall.
Almost all economy graphs of developing countries are going straight up, even though most of the authors have PhD's. The true graphs should always be plateaus, inching ever closer to developed countries, but almost always never fully surpass. Of course there are exceptions, but those are always small countries with small populations.